Akiya Ogawa

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Organization: Osaka Prefecture University , Japan

Department: Department of Applied Chemistry

Title: Professor(PhD)

TOPICS

Organic Chemistry

Phosphine Ligands Organic Photochemistry allene

Chemicals
References

Metal-Free Blue Dye Synthesis: Oxidative Coupling of Benzylamines and N,N-Dimethylanilines to Yield 4,4′-Diaminotriarylmethanes in the Presence of Salicylic Acid as a Co-oxidant

Co-reporter:Chun-ping Dong, Shintaro Kodama, Akinori Uematsu, Akihiro Nomoto, Michio Ueshima, and Akiya Ogawa

The Journal of Organic Chemistry December 1, 2017 Volume 82(Issue 23) pp:12530-12530

Publication Date(Web):November 2, 2017

DOI:10.1021/acs.joc.7b02296

A convenient, novel, and metal-free method for the synthesis of 4,4′-diaminotriarylmethanes (DTMs) is described. This process is based on a one-pot condensation of benzylamines with N,N-dimethylaniline derivatives using 4,6-dihydroxysalicylic acid as a co-oxidant and N-iodosuccinimide as an oxidant. To the best of our knowledge, the present method provides the first reported synthesis of DTMs from benzylamines via oxidative C–N bond cleavage and subsequent double C–C bond formations. The obtained DTMs were then easily converted into a series of blue dyes upon treatment with tetrachloro-1,4-benzoquinone (chloranil). Although the production of triarylmethane dyes tends to require the use of toxic heavy metals, the present method is advantageous in that it is a metal-free and straightforward process.

A Benzoyl Peroxide/Diphenyl Diselenide Binary System for Functionalization of Alkynes Leading to Alkenyl and Alkynyl Selenides

Co-reporter:Shintaro Kodama, Tomokazu Saeki, Kei Mihara, Shinya Higashimae, Shin-ichi Kawaguchi, Motohiro Sonoda, Akihiro Nomoto, and Akiya Ogawa

The Journal of Organic Chemistry December 1, 2017 Volume 82(Issue 23) pp:12477-12477

Publication Date(Web):November 2, 2017

DOI:10.1021/acs.joc.7b02276

Binary systems consisting of benzoyl peroxide (BPO) and diorganyl diselenide are effective in the selective benzoyloxyselenation of internal alkynes to afford the corresponding β-(benzoyloxy)alkenyl selenides in good yields. In contrast to internal alkynes, terminal alkynes undergo a novel C(sp)–H substitution with the phenylseleno group of the BPO/(PhSe)2 system, providing alkynyl selenides in good yields. Both selenation reactions might proceed via benzoyloxy selenide (PhC(O)O–SeAr) as a key intermediate for electrophilic addition to alkynes. The products alkenyl and alkynyl selenides are expected to be useful synthetic intermediates in organic synthesis.

Copper-catalyzed tandem reaction directed toward synthesis of 2,2-disubstituted quinazolinones from vinyl halides and 2-aminobenzamides

Co-reporter:Kotaro Yamaguchi, Shin-ichi Kawaguchi, Motohiro Sonoda, Shinji Tanimori, Akiya Ogawa

Tetrahedron Letters 2017 Volume 58, Issue 43(Issue 43) pp:

Publication Date(Web):25 October 2017

DOI:10.1016/j.tetlet.2017.09.001

•The tandem reaction affords quinazolinones from vinyl halides and 2-aminobenzamides.•A cross-coupling reaction is followed by a hydroamination.•The tandem reaction is used in a one-pot synthesis beginning with an alkyne.A copper-catalyzed tandem reaction with vinyl halides and 2-aminobenzamides has been developed. In this synthetic route, cross-coupling reaction of the amide moiety with vinyl halides initially progresses, followed by hydroamination, to provide 2,2-disubstituted quinazolinone derivatives. Moreover, the tandem reaction is used in a one-pot synthesis beginning with alkyne hydroiodination by PPh3, I2, and H2O.Download high-res image (130KB)Download full-size image

Highly selective photoinduced perfluoroalkylation of vinylsilanes and its application to synthesis of water-shedding polysilanes

Co-reporter:Aya Yoshimura;Akihiro Nomoto;Mari Uchida

Research on Chemical Intermediates 2017 Volume 43( Issue 6) pp:3433-3443

Publication Date(Web):22 January 2016

DOI:10.1007/s11164-016-2424-z

The functionalization of polysilanes is an important subject in materials science because functionalized polysilanes are expected to exhibit potentially innovative properties. This research aims at the addition of a water-shedding property to polysilanes by introducing perfluoroalkyl groups into their skeleton. The photoinduced iodoperfluoroalkylation of various vinylsilanes takes place successfully upon irradiation with a xenon lamp: vinylmonosilanes undergo iodoperfluoroalkylation with perfluoroalkyl iodides (RfI) regioselectively, and the corresponding perfluoroalkylated silanes are obtained in moderate to high yields. Detailed optimization of the photoinduced iodoperfluoroalkylation has been investigated to apply this method to the functionalization of polysilanes. Polysilanes having vinyl groups can be synthesized by the reductive coupling of dichlorovinylsilanes with samarium diiodide (SmI2) and samarium metal (Sm) upon irradiation with visible light. The synthesized vinylpolysilanes and RfI (about 1.0 mM CHCl3 solution) are coated on a glass plate sequentially, and then the following photoirradiation with light of a wavelength over 300 nm successfully adds an excellent water-shedding property to the glass plate.

Gold-Catalyzed Anti-Markovnikov Selective Hydrothiolation of Unactivated Alkenes

Co-reporter:Taichi Tamai, Keiko Fujiwara, Shinya Higashimae, Akihiro Nomoto, and Akiya Ogawa

Organic Letters 2016 Volume 18(Issue 9) pp:2114-2117

Publication Date(Web):April 8, 2016

DOI:10.1021/acs.orglett.6b00746

Despite the widespread use of transition-metal catalysts in organic synthesis, transition-metal-catalyzed reactions of organosulfur compounds, which are known as catalyst poisons, have been difficult. In particular, the transition-metal-catalyzed addition of organosulfur compounds to unactivated alkenes remains a challenge. A novel gold-catalyzed hydrothiolation of unactivated alkenes is presented, which proceeds effectively to give the anti-Markovnikov-selective adducts in good yields and in a regioselective manner.

Photoinduced metal-free diboration of alkynes in the presence of organophosphine catalysts

Co-reporter:Aya Yoshimura, Yuki Takamachi, Kei Mihara, Tomokazu Saeki, Shin-ichi Kawaguchi, Li-Biao Han, Akihiro Nomoto, Akiya Ogawa

Tetrahedron 2016 Volume 72(Issue 48) pp:7832-7838

Publication Date(Web):1 December 2016

DOI:10.1016/j.tet.2016.06.040

In sharp contrast to the transition metal-catalyzed diboration of alkynes with diboron species such as B2pin2, which affords vicinal cis-diborated alkenes, the organophosphine-catalyzed addition of B2pin2 to alkynes proceeds under metal-free conditions upon photoirradiation to give the corresponding vicinal trans-diborated alkenes with good stereoselectivity. For example, the photoinduced diboration of 1-octyne with B2pin2 in the presence of tris(o-methylphenyl)phosphine afforded 1,2-diborated octene with excellent trans selectivity (trans/cis=95/5). The influence of various organophosphines on the diboration is described in detail. The diboration does not occur in the dark or in the absence of an organophosphine catalyst. Moreover, ESR (electron spin resonance) measurements of the reaction mixture revealed a radical species around g=2.003, supporting a radical pathway for the organophosphine-catalyzed diboration. In addition, the photoinduced cis to trans isomerization of vicinal cis-diborated alkenes in the presence/absence of organophosphines is discussed.

Palladium-Catalyzed Markovnikov-Selective Hydroselenation of N-Vinyl Lactams with Selenols Affording N,Se-Acetals

Co-reporter:Taichi Tamai, Megumi Yoshikawa, Shinya Higashimae, Akihiro Nomoto, and Akiya Ogawa

The Journal of Organic Chemistry 2016 Volume 81(Issue 1) pp:324-329

Publication Date(Web):November 30, 2015

DOI:10.1021/acs.joc.5b02431

The highly regioselective hydroselenation of N-vinyl lactams has been revealed to successfully afford the corresponding N,Se-acetals as Markovnikov adducts. In the case of terminal N-vinyl lactams, Markovnikov-selective hydroselenation proceeds efficiently in the absence of any catalyst (or additive), owing to the acidity of the selenols. In contrast, the self-promoted hydroselenation is inefficient with internal N-vinyl lactams. In the presence of palladium diacetate (Pd(OAc)2), however, the desired hydroselenation of internal N-vinyl lactams proceeds efficiently to afford the corresponding N,Se-acetals.

Photoinduced reductive perfluoroalkylation of phosphine oxides: synthesis of P-perfluoroalkylated phosphines using TMDPO and perfluoroalkyl iodides

Co-reporter:Yuki Sato, Shin-ichi Kawaguchi and Akiya Ogawa

Chemical Communications 2015 vol. 51(Issue 52) pp:10385-10388

Publication Date(Web):18 May 2015

DOI:10.1039/C5CC03427B

A photoinduced reaction between TMDPO (diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide) and perfluoroalkyl iodides successfully affords P-(perfluoroalkyl)diphenylphosphines as promising ligands for recyclable catalysts. Interestingly, the perfluoroalkylation reaction involves the reduction of phosphorus(V) compounds to phosphorus(III) species. The advantages of the present reaction include the use of an air-stable phosphorus source and good yields of P-perfluoroalkylphosphines in short reaction times.

Palladium-Catalyzed Synthesis of α-Diimines from Triarylbismuthines and Isocyanides

Co-reporter:Yohsuke Kobiki, Shin-ichi Kawaguchi, and Akiya Ogawa

Organic Letters 2015 Volume 17(Issue 14) pp:3490-3493

Publication Date(Web):July 8, 2015

DOI:10.1021/acs.orglett.5b01566

In this study, we report a highly selective coupling reaction between triarylbismuthines and isocyanides using palladium diacetate as the catalyst, affording α-diimines, with the formation of three C–C bonds. Among several aryl sources (Ar–YLn: Y = B, Sn, Pb, Sb, Bi, I), only triarylbismuthines successfully undergo coupling with isocyanides to selectively afford α-diimines. The coupling reaction exhibits the advantages of high atom economy and convenient operation, with no need for any additive.

Photoinduced Synthesis of P-Perfluoroalkylated Phosphines from Triarylphosphines and Their Application in the Copper-Free Cross-Coupling of Acid Chlorides and Terminal Alkynes

Co-reporter:Shin-ichi Kawaguchi;Yoshiaki Minamida;Takumi Okuda;Yuki Sato;Tomokazu Saeki;Aya Yoshimura;Akihiro Nomoto

Advanced Synthesis & Catalysis 2015 Volume 357( Issue 11) pp:2509-2519

Publication Date(Web):

DOI:10.1002/adsc.201500294

Eco-friendly copper sulfate-catalyzed oxidation of amines to imines by hydrogen peroxide in water

Co-reporter:Kuniaki Marui, Akihiro Nomoto, Michio Ueshima, Akiya Ogawa

Tetrahedron Letters 2015 Volume 56(Issue 10) pp:1200-1202

Publication Date(Web):4 March 2015

DOI:10.1016/j.tetlet.2015.01.090

Imines are very important compounds in organic synthesis, and therefore, their preparation under mild conditions has attracted much attention. In this study, it was found that copper sulfate effectively catalyzes the highly selective oxidation of benzylamines to the corresponding imines with H2O2 in water at room temperature for 1.5 h. This mild and eco-friendly oxidation method could be applied to the oxidation of alkylamines. Therefore, a convenient procedure for the oxidation of amines to the imines has been developed.

Organosulfide-Catalyzed Diboration of Terminal Alkynes under Light

Co-reporter:Dr. Aya Yoshimura;Yuki Takamachi;Dr. Li-Biao Han;Dr. Akiya Ogawa

Chemistry - A European Journal 2015 Volume 21( Issue 40) pp:13930-13933

Publication Date(Web):

DOI:10.1002/chem.201502425

Abstract

An efficient metal-free diboration of terminal alkynes is reported. In the presence of a catalytic amount of organosulfides under light, the addition of bis(pinacolato)diboron (B₂pin₂) to terminal alkynes takes place efficiently to produce the corresponding double borylation products in good yields. Mechanistic studies indicate that this metal-free sulfide-catalyzed diboration of alkynes likely occurs by generation of a boryl-centered radical with the aid of light and a sulfide, since such a radical was detected in the reaction mixture by electron spin resonance (ESR) spectroscopy. The present form of catalysis (sulfide/light) is thought to be unprecedented and provides a new means of preparation for organoboranes without heavy metal contamination in the products, which is highly desired in the preparation of drugs and electronic materials.

Pinacol couplings of a series of aldehydes and ketones with SmI2/Sm/Me3SiCl in DME

Co-reporter:Aya Yoshimura, Tomokazu Saeki, Akihiro Nomoto, Akiya Ogawa

Tetrahedron 2015 Volume 71(Issue 33) pp:5347-5355

Publication Date(Web):19 August 2015

DOI:10.1016/j.tet.2015.06.007

The pinacol coupling is one of the most significant methods to synthesize vic-diols. The combination of samarium diiodide (SmI2) and samarium metal successfully induces the selective pinacol couplings of not only aromatic aldehydes and ketones but also aliphatic ones in the presence of trimethylchlorosilane (Me3SiCl) in 1,2-dimethoxyethane (DME). DME is the most suitable solvent for the reduction system using SmI2 and Me3SiCl. Me3SiCl, a widely available additive, prevents the decomposition of the formed vic-diols, i.e., meso-isomers, and controls their stereochemistry. In particular, the pinacol couplings of sterically hindered aliphatic aldehydes and ketones proceed with excellent diastereoselectivities to afford dl-isomers in good yields.

Selective Thiolative Lactonization of Internal Alkynes Bearing a Hydroxyl Group with Carbon Monoxide and Organic Disulfides Catalyzed by Transition-Metal Complexes

Co-reporter:Shinya Higashimae, Taichi Tamai, Akihiro Nomoto, and Akiya Ogawa

The Journal of Organic Chemistry 2015 Volume 80(Issue 14) pp:7126-7133

Publication Date(Web):June 15, 2015

DOI:10.1021/acs.joc.5b00977

Although many transition-metal catalysts are ineffective for the addition and carbonylative addition of organic disulfides to internal alkynes, dicobalt octacarbonyl and palladium complexes such as Pd(PPh3)4 and Pd(OAc)2 were found to exhibit excellent catalytic activity for the thiolative lactonization of internal alkynes bearing a hydroxyl group. In the presence of the cobalt or palladium catalyst, internal alkynes bearing a hydroxy group, such as homopropargyl alcohol derivatives, successfully undergo thiolative carbonylation with carbon monoxide and an organic disulfide regio- and stereoselectively to afford the corresponding thio group bearing-lactones in good yields. In the Co-catalyzed reaction, the cobalt–alkyne complex from dicobalt octacarbonyl and internal alkyne acts as a key species, making it possible to attain thiolative lactonization of internal alkynes with a hydroxyl group. In the Pd-catalyzed reaction, the coordination of the hydroxy group to the palladium catalyst plays an important role for the thiolative lactonization.

Palladium-Catalyzed Dithiolation of Platinum(II) Alkynylarylacetylides with Diphenyl Disulfide Leading to Construction of -Conjugated Systems with Platinum and Thio Groups

Co-reporter:Md. Mostafizur Rahman;Akihiro Nomoto;Muhammad Younus

European Journal of Inorganic Chemistry 2014 Volume 2014( Issue 16) pp:2613-2617

Publication Date(Web):

DOI:10.1002/ejic.201402098

Abstract

π-Conjugated systems consisting of platinum, sulfur, alkyne, and arene units were synthesized by palladium-catalyzed addition of organic disulfides to platinum acetylides. When diphenyl disulfide was treated with platinum(II) complexes containing extended alkynyl ligands, trans-(R₃P)₂Pt(C≡C–Ar–C≡C–H)₂, in the presence of Pd(PPh₃)₄ catalyst, new sulfur-containing platinum(II) bis(alkenylarylacetylide) complexes were regioselectively synthesized in good yields. The absorption and luminescence spectra indicated that the emission exhibited in the range 411–415 nm depends on the nature of the acetylide ligand bound to platinum.

A convenient hydroiodination of alkynes using I2/PPh3/H2O and its application to the one-pot synthesis of trisubstituted alkenes via iodoalkenes using Pd-catalyzed cross-coupling reactions

Co-reporter:Shin-ichi Kawaguchi, Yuhei Gonda, Haruna Masuno, Huệ Thị Vũ, Kotaro Yamaguchi, Hiroyuki Shinohara, Motohiro Sonoda, Akiya Ogawa

Tetrahedron Letters 2014 Volume 55(Issue 50) pp:6779-6783

Publication Date(Web):10 December 2014

DOI:10.1016/j.tetlet.2014.10.039

A facile hydroiodination of alkynes using readily-available reagents such as I2, PPh3, and H2O has been developed. This is extended to the one-pot synthesis of trisubstituted alkenes from alkynes via iodoalkenes using Pd-catalyzed cross-coupling and related methods such as the Suzuki–Miyaura cross-coupling, Sonogashira cross-coupling reaction, and Mizoroki–Heck reaction.Graphical abstract

Photoinduced Reductive Coupling of Organochlorosilanes with SmI2/Sm

Co-reporter:Aya Yoshimura;Yuri Tomisaka;Zhifang Li;Akihiro Nomoto

Heteroatom Chemistry 2014 Volume 25( Issue 6) pp:684-689

Publication Date(Web):

DOI:10.1002/hc.21186

ABSTRACT

We report efficient reductive dimerization of chlorosilanes with SmI₂/Sm in 1,2-dimethoxyethane upon visible light irradiation. This procedure can be applied to the synthesis of polysilanes from dichlorosilanes. The molecular weight of the obtained polysilanes was higher and their molecular weight distribution was narrower than the polysilanes produced by reactions with SmI₂/Sm in dark.

Regioselective Hydrothiolation of Alkenes Bearing Heteroatoms with Thiols Catalyzed by Palladium Diacetate

Co-reporter:Taichi Tamai and Akiya Ogawa

The Journal of Organic Chemistry 2014 Volume 79(Issue 11) pp:5028-5035

Publication Date(Web):April 30, 2014

DOI:10.1021/jo500586a

In sharp contrast to many examples of transition-metal-catalyzed hydrothiolation of alkynes, the corresponding catalytic addition of thiols to alkenes has remained undeveloped. However, a novel Pd-catalyzed addition of thiols to alkenes bearing a heteroatom, such as oxygen and nitrogen, is found to proceed under mild conditions to give the corresponding Markovnikov adducts, regioselectively, in good yields.

Vanadium-catalyzed green oxidation of benzylic alcohols in water under air atmosphere

Co-reporter:Kuniaki Marui, Yuuki Higashiura, Shintaro Kodama, Suguru Hashidate, Akihiro Nomoto, Shigenobu Yano, Michio Ueshima, Akiya Ogawa

Tetrahedron 2014 70(14) pp: 2431-2438

Publication Date(Web):

DOI:10.1016/j.tet.2014.02.032

Highly regioselective hydroselenation of inactivated terminal alkynes using diselenide–Ph2P(O)H mixed systems under visible-light irradiation

Co-reporter:Yohsuke Kobiki, Shin-ichi Kawaguchi, Akiya Ogawa

Tetrahedron Letters 2013 Volume 54(Issue 40) pp:5453-5456

Publication Date(Web):2 October 2013

DOI:10.1016/j.tetlet.2013.07.127

Upon visible-light irradiation, we could achieve a highly regioselective hydroselenation of inactivated terminal alkynes to give 1-(organylseleno)-1-alkenes by using diselenide–Ph2P(O)H mixed systems. The photoinduced hydroselenation presented in this study is advantageous as it does not involve the handling of oxygen-sensitive and foul-smelling selenols.

Synthesis and Properties of Perfluoroalkyl Phosphine Ligands: Photoinduced Reaction of Diphosphines with Perfluoroalkyl Iodides

Co-reporter:Dr. Shin-ichi Kawaguchi;Yoshiaki Minamida;Takashi Ohe;Dr. Akihiro Nomoto;Dr. Motohiro Sonoda ;Dr. Akiya Ogawa

Angewandte Chemie International Edition 2013 Volume 52( Issue 6) pp:1748-1752

Publication Date(Web):

DOI:10.1002/anie.201207383

Synthesis and Properties of Perfluoroalkyl Phosphine Ligands: Photoinduced Reaction of Diphosphines with Perfluoroalkyl Iodides

Co-reporter:Dr. Shin-ichi Kawaguchi;Yoshiaki Minamida;Takashi Ohe;Dr. Akihiro Nomoto;Dr. Motohiro Sonoda ;Dr. Akiya Ogawa

Angewandte Chemie 2013 Volume 125( Issue 6) pp:1792-1796

Publication Date(Web):

DOI:10.1002/ange.201207383

Novel reducing properties of a series of lanthanoid metals in the presence of SmI2

Co-reporter:Yuri Tomisaka;Aya Yoshimura;Akihiro Nomoto

Research on Chemical Intermediates 2013 Volume 39( Issue 1) pp:43-48

Publication Date(Web):2013 January

DOI:10.1007/s11164-012-0630-x

The reduction of dodecyl iodide, as model compound, with a series of lanthanoid (Ln) metals in the presence of catalytic amounts of samarium diiodide (SmI2) has been investigated in detail. The reducing activity of SmI2/Ln and the kinds of reduced products were found to be dependent on the individual Ln, but not on SmI2.

A highly selective cobalt-catalyzed carbonylative cyclization of internal alkynes with carbon monoxide and organic thiols

Co-reporter:Yoshihiro Higuchi, Shinya Higashimae, Taichi Tamai, Akiya Ogawa

Tetrahedron 2013 69(52) pp: 11197-11202

Publication Date(Web):

DOI:10.1016/j.tet.2013.10.080

Highly selective perfluoroalkylchalcogenation of alkynes by the combination of iodoperfluoroalkanes and organic dichalcogenides upon photoirradiation

Co-reporter:Taichi Tamai, Akihiro Nomoto, Kaname Tsuchii, Yoshiaki Minamida, Takenori Mitamura, Motohiro Sonoda, Akiya Ogawa

Tetrahedron 2012 68(51) pp: 10516-10522

Publication Date(Web):

DOI:10.1016/j.tet.2012.09.026

Highly regioselective hydroiodination of terminal alkynes and silylalkynes with iodine and phosphorus reagents leading to internal iodoalkenes

Co-reporter:Shin-ichi Kawaguchi, Haruna Masuno, Motohiro Sonoda, Akihiro Nomoto, Akiya Ogawa

Tetrahedron 2012 68(47) pp: 9818-9825

Publication Date(Web):

DOI:10.1016/j.tet.2012.08.096

Novel Heterotetranuclear V2Mo2 or V2W2 Complexes with 4,4′-Di-tert-butyl-2,2′-bipyridine: Syntheses, Crystal Structures, and Catalytic Activities

Co-reporter:Shintaro Kodama, Akihiro Nomoto, Shigenobu Yano, Michio Ueshima, and Akiya Ogawa

Inorganic Chemistry 2011 Volume 50(Issue 20) pp:9942-9947

Publication Date(Web):September 9, 2011

DOI:10.1021/ic2009094

Two novel heterotetranuclear complexes [V2O2(μ-MeO)2(μ-WO4)2(4,4′-tBubpy)2] (1) and [V2O2(μ-MeO)2(μ-MoO4)2(4,4′-tBubpy)2] (2) were synthesized, and the solid state structures of these complexes were revealed by single crystal X-ray crystallography. The heterotetranuclear complexes 1 and 2 are centrosymmetric building blocks, considered as consisting of two [VO(4,4′-tBubpy)]3+ units bridged by μ-MO42– (M = W or Mo) anions connected with methoxy groups. Furthermore, catalytic activities of 1 and 2 in the alcohol oxidation with hydrogen peroxide as terminal oxidants in water as solvent were investigated.

Photochemical intramolecular cyclization of o-alkynylaryl isocyanides with organic dichalcogenides leading to 2,4-bischalcogenated quinolines

Co-reporter:Takenori Mitamura, Kimiyo Iwata, Akihiro Nomoto and Akiya Ogawa

Organic & Biomolecular Chemistry 2011 vol. 9(Issue 10) pp:3768-3775

Publication Date(Web):22 Mar 2011

DOI:10.1039/C0OB01168A

When a mixture of o-alkynylaryl isocyanides and organic dichalcogenides such as diselenides or ditellurides was irradiated with light of wavelength over 300 or 400 nm, the intramolecular cyclization of the isocyanides took place to afford the corresponding 2,4-bischalcogenated quinolines selectively. The photochemical cyclization of 2-(phenylethynyl)phenyl isocyanide could also proceed in the presence of hydrogen transfer reagents such as tris(trimethylsilyl)silane, tributylgermyl hydride, alkanethiols, and benzeneselenol, providing the corresponding 3-phenylquinoline as the result of 2,4-dihydrogenation.

Photoinduced Intramolecular Cyclization of o-Ethenylaryl Isocyanides with Organic Disulfides Mediated by Diphenyl Ditelluride

Co-reporter:Takenori Mitamura, Kimiyo Iwata, and Akiya Ogawa

The Journal of Organic Chemistry 2011 Volume 76(Issue 10) pp:3880-3887

Publication Date(Web):April 4, 2011

DOI:10.1021/jo200299d

Photoinduced reaction of o-ethenylaryl isocyanides with organic disulfides in the presence of diphenyl ditellurides affords the corresponding bisthiolated indole derivatives via a radical cyclization process. The cyclization can proceed at room temperature upon visible-light irradiation and exhibits good tolerance to functional groups. Several organic disulfides also can be employed for this cyclization, and the corresponding bisthiolated indole derivatives are obtained selectively. In addition, the photoinduced reaction of o-ethenylaryl isocyanides with bis(2-aminophenyl) disulfide affords tetracyclic compounds in one portion.

Rhodium-Catalyzed Highly Stereoselective Hydroselenation of Internal Alkynes Bearing an Electron-withdrawing Group

Co-reporter:Shin-ichi Kawaguchi, Mao Kotani, Shingo Atobe, Akihiro Nomoto, Motohiro Sonoda, and Akiya Ogawa

Organometallics 2011 Volume 30(Issue 24) pp:6766-6769

Publication Date(Web):December 2, 2011

DOI:10.1021/om200663k

Rhodium-catalyzed highly regio- and stereoselective hydroselenation of internal alkynes bearing an electron-withdrawing group took place to give (E)-vinyl selenides in good yields. The excellent syn stereoselectivity of this rhodium-catalyzed hydroselenation is of great importance in terms of complementing the previously reported hydroselenation of alkynes.

Cobalt-Catalyzed Thiolative Lactonization of Alkynes with Double CO Incorporation

Co-reporter:Yoshihiro Higuchi, Shingo Atobe, Michiru Tanaka, Ikuyo Kamiya, Takuya Yamamoto, Akihiro Nomoto, Motohiro Sonoda, and Akiya Ogawa

Organometallics 2011 Volume 30(Issue 17) pp:4539-4543

Publication Date(Web):August 11, 2011

DOI:10.1021/om200248f

When the Co2(CO)8-catalyzed reaction of alkynes with thiols is conducted under the pressure of carbon monoxide, a novel thiolative lactonization with simultaneous introduction of two carbon monoxide molecules into the carbon–carbon triple bonds takes place successfully to afford α,β-unsaturated γ-thio-γ-lactones with excellent regioselectivity.

Highly regioselective hydroselenation and double-bond isomerization of terminal alkynes with benzeneselenol catalyzed by bis(triphenylphosphine)palladium(II) dichloride

Co-reporter:Toshiya Ozaki, Mao Kotani, Hiroki Kusano, Akihiro Nomoto, Akiya Ogawa

Journal of Organometallic Chemistry 2011 696(1) pp: 450-455

Publication Date(Web):

DOI:10.1016/j.jorganchem.2010.10.005

Highly Selective Hydroiodation of Alkynes Using an Iodine−Hydrophosphine Binary System

Co-reporter:Shin-ichi Kawaguchi and Akiya Ogawa

Organic Letters 2010 Volume 12(Issue 9) pp:1893-1895

Publication Date(Web):April 1, 2010

DOI:10.1021/ol1005246

A novel hydroiodation of alkynes (1) using an iodine/hydrophosphine binary system takes place regioselectively to provide the corresponding Markovnikov-type adducts (2) in good yield. This hydroiodation is advantageous in terms of mild conditions, convenient operation, and tolerance to various functional groups.

Palladium-catalyzed alkynylselenation of acetylenedicarboxylates leading to enyne selenides and application to synthesis of multisubstituted aryl selenides

Co-reporter:Takenori Mitamura, Akiya Ogawa

Tetrahedron Letters 2010 Volume 51(Issue 27) pp:3538-3541

Publication Date(Web):7 July 2010

DOI:10.1016/j.tetlet.2010.04.125

Direct conversion of benzylamines to imines via atmospheric oxidation in the presence of VO(Hhpic)2 catalyst

Co-reporter:Shintaro Kodama, Jun Yoshida, Akihiro Nomoto, Yukihiro Ueta, Shigenobu Yano, Michio Ueshima, Akiya Ogawa

Tetrahedron Letters 2010 Volume 51(Issue 18) pp:2450-2452

Publication Date(Web):5 May 2010

DOI:10.1016/j.tetlet.2010.02.150

Oxovanadium complex bearing 3-hydroxypicolinic acid (H2hpic), that is, VO(Hhpic)2, successfully catalyzes a highly selective oxidation of benzylamines to the corresponding N-(benzylidene)benzylamines under atmospheric molecular oxygen. In addition, the use of imidazolium-type ionic liquids as solvent makes it possible to attain recycling of the catalyst.

Reductive carboxylation of alkyl halides with CO2 by use of photoinduced SmI2/Sm reduction system

Co-reporter:Akihiro Nomoto, Yusuke Kojo, Go Shiino, Yuri Tomisaka, Ikuko Mitani, Masahiko Tatsumi, Akiya Ogawa

Tetrahedron Letters 2010 Volume 51(Issue 50) pp:6580-6583

Publication Date(Web):15 December 2010

DOI:10.1016/j.tetlet.2010.10.028

Upon visible-light irradiation, reductive carboxylation of alkyl halides takes place by using a SmI2/Sm mixed system under atmospheric CO2 to afford the corresponding carboxylic acids in good to excellent yields.

Highly Selective Phosphinotelluration of Terminal Alkynes Using a (Ph2P)2−(PhTe)2 Mixed System upon Visible Light Irradiation: Straightforward Access to 1-Phosphino-2-telluro-alkenes

Co-reporter:Shin-ichi Kawaguchi, Takashi Ohe, Takamune Shirai, Akihiro Nomoto, Motohiro Sonoda and Akiya Ogawa

Organometallics 2010 Volume 29(Issue 2) pp:312-316

Publication Date(Web):December 16, 2009

DOI:10.1021/om9008982

Simultaneous and regioselective introduction of both phosphino and telluro groups into carbon−carbon triple bonds has been attained successfully by using a novel mixed system of diphosphine and ditelluride under visible light irradiation conditions. Upon irradiation with a xenon lamp (500 W) through the filter (hν > 400 nm), terminal alkynes undergo highly selective phosphinotelluration in the presence of tetraphenyldiphosphine and diphenyl ditelluride, affording 1-(diphenylphosphino)-2-(phenyltelluro)alkenes, regioselectively, in moderate to good yields. The regioselectivity of this phosphinotelluration of terminal alkynes is discussed by comparison with those of the thiophosphination using a (Ph2P)2−(PhS)2 binary system and the selenophosphination using a (Ph2P)2−(PhSe)2 binary system.

(PhTe)2-Mediated Intramolecular Radical Cyclization of o-Ethynylaryl Isocyanides Leading to Bistellurated Quinolines upon Visible-Light Irradiation

Co-reporter:Takenori Mitamura, Kimiyo Iwata and Akiya Ogawa

Organic Letters 2009 Volume 11(Issue 15) pp:3422-3424

Publication Date(Web):July 9, 2009

DOI:10.1021/ol901267h

Upon treatment with (PhTe)2 under visible-light irradiation, o-ethynylaryl isocyanides underwent intramolecular radical cyclization with introduction of telluro groups, affording the corresponding bistellurated quinolines.

Copper(0)-Induced Deselenative Insertion of N,N-Disubstituted Selenoamides into Acetylenic C−H Bond Leading to Propargylamines

Co-reporter:Takenori Mitamura and Akiya Ogawa

Organic Letters 2009 Volume 11(Issue 10) pp:2045-2048

Publication Date(Web):April 15, 2009

DOI:10.1021/ol9001976

Upon heating at 110 °C in the presence of copper(0) powder, terminal acetylenes undergo a novel deselenative C−H bond insertion reaction of N,N-disubstituted selenoamides, affording the corresponding propargylamines in good to excellent yields, selectively.

Tetranuclear vanadium complex, (VO)4(hpic)4: a recyclable catalyst for oxidation of benzyl alcohols with molecular oxygen

Co-reporter:Shintaro Kodama, Yukihiro Ueta, Jun Yoshida, Akihiro Nomoto, Shigenobu Yano, Michio Ueshima and Akiya Ogawa

Dalton Transactions 2009 (Issue 44) pp:9708-9711

Publication Date(Web):15 Sep 2009

DOI:10.1039/B913823D

Vanadium(IV) complexes bearing 3-hydroxypicolinic acid (H2hpic) as ligands, VO(Hhpic)2 (1) and the cyclic tetramer (VO)4(hpic)4 (2), have excellent catalytic ability for the oxidation of a variety of primary and secondary benzyl alcohols with molecular oxygen in acetonitrile or protic solvents such as ethanol and water, affording the corresponding aldehydes and ketones, respectively. Construction of multi-nuclear complexes by the selection of ligands attains higher turnover numbers and recycling of the catalyst.

Photoinduced hydrophosphinylation of alkenes with diphenylphosphine oxide

Co-reporter:Shin-ichi Kawaguchi, Akihiro Nomoto, Motohiro Sonoda, Akiya Ogawa

Tetrahedron Letters 2009 50(6) pp: 624-626

Publication Date(Web):

DOI:10.1016/j.tetlet.2008.11.079

On the potentially excellent reducing ability of a series of low-valent rare earths induced by photoirradiation

Co-reporter:Yuri Tomisaka, Akihiro Nomoto, Akiya Ogawa

Tetrahedron Letters 2009 50(5) pp: 584-586

Publication Date(Web):

DOI:10.1016/j.tetlet.2008.11.077

Metal-Free Oxidative Coupling of Benzylamines to Imines under an Oxygen Atmosphere Promoted Using Salicylic Acid Derivatives as Organocatalysts

Co-reporter:Chun-ping Dong, Yuuki Higashiura, Kuniaki Marui, Shun Kumazawa, Akihiro Nomoto, Michio Ueshima, and Akiya Ogawa

ACS Omega Volume 1(Issue 5) pp:799-807

Publication Date(Web):November 4, 2016

DOI:10.1021/acsomega.6b00235

The oxidative coupling of benzylamines proceeds efficiently using salicylic acid derivatives as organocatalysts under an oxygen atmosphere, affording the corresponding N-benzylidenebenzylamines in high yields. Electron-rich salicylic acid derivatives such as 4,6-dimethoxysalicylic acid and 4,6-dihydroxysalicylic acid exhibit excellent catalytic activities for the oxidative coupling of benzylamines to give the corresponding imines. This amine oxidation can also be applied to the synthesis of nitrogen-containing heterocycles such as benzimidazole derivatives. Furthermore, to recycle the catalyst, silica gel supported with 4.7 wt % of 4,6-dihydroxysalicylic acid is prepared, which acts as a recyclable catalyst, oxidizing benzylamine to imine four times successfully.Topics: Catalysts; Green chemistry; Organic compounds and Functional groups; Redox reaction; Redox reaction;

Tetranuclear vanadium complex, (VO)4(hpic)4: a recyclable catalyst for oxidation of benzyl alcohols with molecular oxygen

Co-reporter:Shintaro Kodama, Yukihiro Ueta, Jun Yoshida, Akihiro Nomoto, Shigenobu Yano, Michio Ueshima and Akiya Ogawa

Dalton Transactions 2009(Issue 44) pp:NaN9711-9711

Publication Date(Web):2009/09/15

DOI:10.1039/B913823D

Photoinduced reductive perfluoroalkylation of phosphine oxides: synthesis of P-perfluoroalkylated phosphines using TMDPO and perfluoroalkyl iodides

Co-reporter:Yuki Sato, Shin-ichi Kawaguchi and Akiya Ogawa

Chemical Communications 2015 - vol. 51(Issue 52) pp:NaN10388-10388

Publication Date(Web):2015/05/18

DOI:10.1039/C5CC03427B

Photochemical intramolecular cyclization of o-alkynylaryl isocyanides with organic dichalcogenides leading to 2,4-bischalcogenated quinolines

Co-reporter:Takenori Mitamura, Kimiyo Iwata, Akihiro Nomoto and Akiya Ogawa