Itaru Nakamura

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Organization: Tohoku University

Department: 1 Research and Analytical Center for Giant Molecules, Graduate School of Science

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Chemicals
References

Concerted [1,3]-Rearrangement in Cationic Cobalt-Catalyzed Reaction of O-(Alkoxycarbonyl)-N-arylhydroxylamines

Co-reporter:Itaru Nakamura, Mao Owada, Takeru Jo, and Masahiro Terada

Organic Letters April 21, 2017 Volume 19(Issue 8) pp:

Publication Date(Web):April 3, 2017

DOI:10.1021/acs.orglett.7b00700

O-(Alkoxycarbonyl)-N-arylhydroxylamines were efficiently converted to 2-aminophenol derivatives by cationic cobalt catalysts at 30 °C. The results of 18O-labeling experiments suggested that rearrangement of the alkoxycarbonyl group from the aniline nitrogen to the ortho position proceeded in an unprecedented [1,3] manner.

Efficient synthesis of multisubstituted 2-alkenylpyridines via 2,3-rearrangement of O-homoallenylic oximes

Co-reporter:Itaru Nakamura;Yoshiharu Oyama;Dong Zhang;Masahiro Terada

Organic Chemistry Frontiers 2017 vol. 4(Issue 6) pp:1034-1036

Publication Date(Web):2017/05/31

DOI:10.1039/C6QO00703A

O-Homoallenylic α,β-unsaturated oximes were efficiently converted to the corresponding 2-alkenylpyridine derivatives by microwave irradiation. The present reaction proceeds via 2,3-rearrangement followed by 6π-electrocyclization of the resulting N-(2-dienyl)nitrone intermediate serving as a 3-azatriene.

Efficient Synthesis of Enantioenriched Isoxazoles by Chirality Transfer in Gold-Catalyzed Cyclization/Methylene-Group Transfer Followed by Carbonyl Ene Reaction

Co-reporter:Shinya Gima;Masahiro Terada

European Journal of Organic Chemistry 2017 Volume 2017(Issue 30) pp:4375-4378

Publication Date(Web):2017/08/17

DOI:10.1002/ejoc.201700708

Enantioenriched isoxazoles having a chiral side chain at the 4-position were efficiently synthesized by chirality transfer in a gold-catalyzed cyclization/intermolecular methylene-transfer sequence followed by a carbonyl ene reaction. The chiral information of the enantioenriched O-propargylic oximes was completely retained during the gold-catalyzed reaction. The subsequent carbonyl ene reaction between the resulting 4-methylenated isoxazoline and glyoxylates proceeded with excellent levels of chirality transfer by using BF3·OEt2 as a Lewis acid. According to the relationship of absolute configuration between the starting propargylic oxime and the obtained alcohol having an isoxazole, the carbonyl ene reaction proceeded in an endo manner.

Copper-Catalyzed Skeletal Rearrangements of O-Propargylic Oximes via Cleavage of a CarbonOxygen Bond

Co-reporter:Itaru Nakamura;Masahiro Terada

The Chemical Record 2015 Volume 15( Issue 2) pp:429-444

Publication Date(Web):

DOI:10.1002/tcr.201402088

Abstract

In this account, we describe recent developments in copper-catalyzed skeletal 2,3-rearrangement reactions of O-propargylic oximes to form four-membered cyclic nitrones, pyridine N-oxides, and amidodienes via N-allenylnitrone intermediates. The sequence of events leading up to our encounter with O-propargylic oximes is also presented.

Skeletal Rearrangement of O-Propargylic Formaldoximes by a Gold-Catalyzed Cyclization/Intermolecular Methylene Transfer Sequence

Co-reporter:Dr. Itaru Nakamura;Shinya Gima;Yu Kudo;Dr. Masahiro Terada

Angewandte Chemie 2015 Volume 127( Issue 24) pp:7260-7263

Publication Date(Web):

DOI:10.1002/ange.201501856

Abstract

Skeletal rearrangement of O-propargylic formaldoximes, in the presence of gold catalysts, afforded 4-methylene-2-isoxazolines in good to excellent yields by an intermolecular methylene transfer. In addition, the cascade reaction with maleimide in the presence of a gold catalyst afforded isoxazole derivatives by cyclization/methylene transfer and a subsequent ene reaction, whereas that using a copper catalyst gave oxazepines through a 2,3-rearrangement.

Skeletal Rearrangement of O-Propargylic Formaldoximes by a Gold-Catalyzed Cyclization/Intermolecular Methylene Transfer Sequence

Co-reporter:Dr. Itaru Nakamura;Shinya Gima;Yu Kudo;Dr. Masahiro Terada

Angewandte Chemie International Edition 2015 Volume 54( Issue 24) pp:7154-7157

Publication Date(Web):

DOI:10.1002/anie.201501856

Abstract

Efficient Synthesis of N-Alkylated α,β-Unsaturated Ketonitrones via Cu-Catalyzed Rearrangement

Co-reporter:Itaru Nakamura, Toshiki Onuma, Ryo Kanazawa, Yuki Nishigai, and Masahiro Terada

Organic Letters 2014 Volume 16(Issue 16) pp:4198-4200

Publication Date(Web):July 24, 2014

DOI:10.1021/ol501889g

N-Alkylated unsaturated ketonitrones were efficiently synthesized from propargyloxyamines using Cu catalysts. Mechanistic studies suggest that the rearrangement reaction proceeds via Cu-catalyzed intramolecular hydroamination, followed by thermally induced electrocyclic ring opening.

Cu-Catalyzed Skeletal Rearrangement of O-Propargylic Electron-Rich Arylaldoximes into Amidodienes

Co-reporter:Itaru Nakamura, Yasuhiro Ishida, and Masahiro Terada

Organic Letters 2014 Volume 16(Issue 9) pp:2562-2565

Publication Date(Web):April 21, 2014

DOI:10.1021/ol5009608

O-Propargylic oximes that possess an electron-rich p-(dimethylamino)phenyl group at the oxime moiety and an alkyl group at the propargylic position were efficiently converted in the presence of Cu(I) catalysts to the corresponding 1-amidodienes in good to excellent yields. The reaction proceeded via a 2,3-rearrangement, followed by isomerization of the resulting N-allenylnitrone to the amide, presumably through the oxaziridine intermediate.

Copper-Catalyzed Cascade Transformation of O-Propargylic Oximes with Sulfonyl Azides to α,β-Unsaturated N-Acylamidines

Co-reporter:Dong Zhang, Itaru Nakamura, and Masahiro Terada

Organic Letters 2014 Volume 16(Issue 19) pp:5184-5187

Publication Date(Web):September 16, 2014

DOI:10.1021/ol502541w

Copper-catalyzed cascade transformations of O-propargylic oximes and sulfonyl azides were carried out to efficiently afford α,β-unsaturated N-acylamidines. The reaction involved the intramolecular attack of the oxime group to the ketenimine moiety that was generated in situ, followed by the cleavage of the N–O bond.

Synthesis of 1,6-dihydropyrimidines via copper-catalyzed multistep cascade reactions between O-propargylic aldoximes and isocyanates

Co-reporter:Itaru Nakamura, Toshiki Onuma, Dong Zhang, Masahiro Terada

Tetrahedron Letters 2014 Volume 55(Issue 6) pp:1178-1182

Publication Date(Web):5 February 2014

DOI:10.1016/j.tetlet.2013.12.105

Multi-step cascade reactions of O-propargylic oximes with isocyanates were carried out in the presence of copper catalysts to afford the corresponding 1,6-dihydropyrimidines in good yields. The multi-step reactions consisted of a 2,3-rearrangement, a [3+2] cycloaddition, decarboxylative ring opening involving a 1,4-hydrogen shift, and a 6π-electrocyclization.

Efficient Synthesis of Eight-Membered Nitrogen Heterocycles from O-Propargylic Oximes by Rhodium-Catalyzed Cascade Reactions

Co-reporter:Dr. Itaru Nakamura;Yoshinori Sato;Keisuke Takeda;Dr. Masahiro Terada

Chemistry - A European Journal 2014 Volume 20( Issue 33) pp:10214-10219

Publication Date(Web):

DOI:10.1002/chem.201403637

Abstract

Azocine derivatives were successfully synthesized from O-propargylic oximes by means of a Rh-catalyzed 2,3-rearrangement/heterocyclization cascade reaction. Moreover, the chirality of the substrate was maintained throughout the cascade process to afford the corresponding optically active azocines.

Oxazepine Synthesis by Copper-Catalyzed Intermolecular Cascade Reactions between O-Propargylic Oximes and Dipolarophiles

Co-reporter:Dr. Itaru Nakamura;Yu Kudo;Dr. Masahiro Terada

Angewandte Chemie International Edition 2013 Volume 52( Issue 29) pp:7536-7539

Publication Date(Web):

DOI:10.1002/anie.201302751

Oxazepine Synthesis by Copper-Catalyzed Intermolecular Cascade Reactions between O-Propargylic Oximes and Dipolarophiles

Co-reporter:Dr. Itaru Nakamura;Yu Kudo;Dr. Masahiro Terada

Angewandte Chemie 2013 Volume 125( Issue 29) pp:7684-7687

Publication Date(Web):

DOI:10.1002/ange.201302751

Copper-Catalyzed Skeletal Rearrangement of O-Propargylic Alkylaldoximes via N–O Bond Cleavage

Co-reporter:Itaru Nakamura, Tomoki Iwata, Dong Zhang, and Masahiro Terada

Organic Letters 2012 Volume 14(Issue 1) pp:206-209

Publication Date(Web):December 14, 2011

DOI:10.1021/ol203001w

O-Propargylic oximes that possess a proton at the α-position of the oxime group were effectively converted to the corresponding oxiranyl N-alkenylimines via a 5-endo-dig cyclization followed by the cleavage of the N–O bond.

Synthesis of Azepine Derivatives by Rhodium-Catalyzed Tandem 2,3-Rearrangement/Heterocyclization

Co-reporter:Dr. Itaru Nakamura;Masashi Okamoto;Yoshinori Sato;Dr. Masahiro Terada

Angewandte Chemie 2012 Volume 124( Issue 43) pp:10974-10977

Publication Date(Web):

DOI:10.1002/ange.201205285

Titelbild: Synthesis of Azepine Derivatives by Rhodium-Catalyzed Tandem 2,3-Rearrangement/Heterocyclization (Angew. Chem. 43/2012)

Co-reporter:Dr. Itaru Nakamura;Masashi Okamoto;Yoshinori Sato;Dr. Masahiro Terada

Angewandte Chemie 2012 Volume 124( Issue 43) pp:

Publication Date(Web):

DOI:10.1002/ange.201207154

Synthesis of Azepine Derivatives by Rhodium-Catalyzed Tandem 2,3-Rearrangement/Heterocyclization

Co-reporter:Dr. Itaru Nakamura;Masashi Okamoto;Yoshinori Sato;Dr. Masahiro Terada

Angewandte Chemie International Edition 2012 Volume 51( Issue 43) pp:10816-10819

Publication Date(Web):

DOI:10.1002/anie.201205285

Cover Picture: Synthesis of Azepine Derivatives by Rhodium-Catalyzed Tandem 2,3-Rearrangement/Heterocyclization (Angew. Chem. Int. Ed. 43/2012)

Co-reporter:Dr. Itaru Nakamura;Masashi Okamoto;Yoshinori Sato;Dr. Masahiro Terada

Angewandte Chemie International Edition 2012 Volume 51( Issue 43) pp:

Publication Date(Web):

DOI:10.1002/anie.201207154

Thermally-induced skeletal rearrangement of (Z)-O-propargylic α,β-unsaturated aldoximes to multisubstituted pyridine oxides

Co-reporter:Itaru Nakamura, Dong Zhang, Masahiro Terada

Tetrahedron Letters 2011 Volume 52(Issue 48) pp:6470-6472

Publication Date(Web):30 November 2011

DOI:10.1016/j.tetlet.2011.09.107

(Z)-Propargylic oxime ethers derived from α,β-unsaturated aldehydes were converted to the corresponding 2,3,6-trisubstituted pyridine oxides in moderate to acceptable yields with high regioselectivity. The reaction proceeds via a tandem thermal [2,3] rearrangement, 4π electrocyclization, and ring expansion.

Copper-Catalyzed Rearrangement of (Z)-Propynal Hydrazones via N−N Bond Cleavage

Co-reporter:Itaru Nakamura, Naozumi Shiraiwa, Ryo Kanazawa, and Masahiro Terada

Organic Letters 2010 Volume 12(Issue 18) pp:4198-4200

Publication Date(Web):August 18, 2010

DOI:10.1021/ol1017504

Propynal hydrazones are successfully converted to the corresponding 3-aminoacrylonitriles in the presence of copper catalysts in good to high yields. As an example, (Z)-N-(hex-2-ynylidene)morpholin-4-amine reacted in the presence of 10 mol % Cu(OAc)2 in acetonitrile at 25 °C to afford (E)-3-morpholinohex-2-enenitrile ((E)-2 h) in 77% yield via C−N bond formation and subsequent β-elimination involving cleavage of N−N and C−H bonds.

N-Allenylnitrone acts as 2-azadiene in the Cu-catalyzed cascade reaction of O-propargylic oximes with azodicarboxylates

Co-reporter:Itaru Nakamura, Takeru Jo, Dong Zhang and Masahiro Terada

Inorganic Chemistry Frontiers 2014 - vol. 1(Issue 8) pp:NaN918-918

Publication Date(Web):2014/07/07

DOI:10.1039/C4QO00156G

The reaction of O-propargylic oximes with azodicarboxylates efficiently afforded 1,2,4-triazine oxides in good yields. The key intermediate, N-allenylnitrone, acted as 2-azadiene, undergoing stepwise [4 + 2] cycloaddition.

Efficient synthesis of multisubstituted 2-alkenylpyridines via 2,3-rearrangement of O-homoallenylic oximes

Co-reporter:Itaru Nakamura, Yoshiharu Oyama, Dong Zhang and Masahiro Terada

Inorganic Chemistry Frontiers 2017 - vol. 4(Issue 6) pp:NaN1036-1036

Publication Date(Web):2017/02/09

DOI:10.1039/C6QO00703A