Enantioselective synthesis of polycyclic nitrogen, oxygen, and sulfur heterocycles by rhodium-catalyzed intramolecular alkene hydroacylation is reported. The intramolecular hydroacylation reactions generate 1,4-dihydrocyclopenta[b]indol-3(2H)-ones and 3,4-dihydrocyclopenta[b]indol-1(2H)-one in moderate-to-high yields (65–99%) with good-to-excellent enantioselectivities (84–99% ee). The catalyst system also promotes alkene hydroacylation of 3-vinylfuran-, 3-vinylbenzothiophene-, and 3-vinylthiophene-2-carboxaldehydes to generate the corresponding ketone products in moderate-to-high yields (71–91% yield) with excellent enantioselectivities (97–99% ee).

We report enantioselective, palladium-catalyzed conjugate additions of arylboronic acids to β-aryl, β,β-disubstituted enones to generate ketones containing bis-benzylic quaternary stereocenters. A catalyst generated from palladium trifluoroacetate and (S)-4-tert-butyl-2-(2-pyridyl)oxazoline ligand ((S)-t-BuPyOx) promotes conjugate additions of a wide range of arylboronic acids to a variety of β-aryl, β,β-disubstituted enones. Iterative addition of the arylboronic acid to minimize undesired protodeboronation pathways leads to efficient formation of the corresponding ketones containing bis-benzylic quaternary stereocenters in up to 92% yield and up to 93% enantioselectivity.

We report Ni-catalyzed formal carboacylation of o-allylbenzamides with arylboronic acid pinacol esters. The reaction is triggered by oxidative addition of an activated amide C–N bond to a Ni(0) catalyst and proceeds via alkene insertion into a Ni(II)–acyl bond. The exo-selective carboacylation reaction generates 2-benzyl-2,3-dihydro-1H-inden-1-ones in moderate to high yields (46–99%) from a variety of arylboronic acid pinacol esters and substituted o-allylbenzamides. These results show that amides are practical substrates for alkene carboacylation via amide C–N bond activation, and this approach bypasses challenges associated with alkene carboacylation triggered by C–C bond activation.

A series of mixed-linker bipyridyl metal–organic framework (MOF)-supported palladium(II) catalysts were used to elucidate the electronic and steric effects of linker substitution on the activity of these catalysts in the context of Suzuki–Miyaura cross-coupling reactions. m-6,6′-Me2bpy-MOF-PdCl2 exhibited 110- and 496-fold enhancements in activity compared to nonfunctionalized m-bpy-MOF-PdCl2 and m-4,4′-Me2bpy-MOF-PdCl2, respectively. This result clearly demonstrates that the stereoelectronic properties of metal-binding linker units are critical to the activity of single-site organometallic catalysts in MOFs and highlights the importance of linker engineering in the design and development of efficient MOF catalysts.Keywords: bipyridyl linker; heterogeneous catalysis; isoreticular metal−organic frameworks; single-site catalyst; structure−activity relationship; Suzuki−Miyaura cross-coupling

We report a strategy that combines alkene hydroacylation and enantioselective α-(hetero)arylation reactions to form a wide variety of nitrogen-containing heterocyclic ketones bearing α-chiral quaternary stereogenic centers. Exo-selective, intramolecular Ni-catalyzed hydroacylations of N-homoallylindole- and N-homoallylpyrrole-2-carboxaldehydes form α-substituted six-membered heterocyclic ketones in up to 95% yield, while N-heterocyclic carbene (NHC) catalyzed hydroacylations of N-allylindole- and N-allylpyrrole-2-carboxaldehydes form α-substituted five-membered heterocyclic ketones in up to 99% yield. The racemic five- and six-membered products of Ni- and NHC-catalyzed hydroacylation reactions are readily transformed into heterocyclic ketones containing an α-chiral quaternary stereogenic center by enantioselective Ni-catalyzed α-arylation and α-heteroarylation reactions. The chiral, nonracemic products formed through a combination of alkene hydroacylation and α-(hetero)arylation reactions are formed in moderate to high yields (44–99%) with excellent enantioselectivities (typically >95% ee). The identity of the precatalyst for Ni-catalyzed α-(hetero)arylation is dictated by the identity of the α-substituted heterocyclic ketone starting material. α-(Hetero)arylations of six-membered heterocyclic ketones occur at 65–85 °C in the presence of a catalyst generated in situ from Ni(COD)2 and (R)-BINAP or (R)-DIFLUORPHOS. α-(Hetero)arylation of five-membered heterocyclic ketones must be conducted at room temperature in the presence of an [((R)-BINAP)Ni(η2-NC-Ph)] precatalyst or a catalyst generated in situ from Ni(COD)2, (R)-DIFLUORPHOS, and benzonitrile.Keywords: alkene hydroacylation; enantioselective catalysis; heterocycles; ketone α-arylation; quaternary stereocenters

•A catalytic method for synthesis of substituted flavanone derivatives is reported.•The catalyst system minimizes protodeboronation and biaryl formation processes.•The reactions encompass a range of arylboronic acids and 2-alkylchromanones.Palladium-catalyzed conjugate additions of arylboronic acids to 2-alkylchromones are reported. The conjugate additions occur in aqueous media in the presence of a catalyst generated from palladium trifluoroacetate and 1,10-phenanthroline, and the flavanone derivatives containing a fully-substituted carbon center are formed in up to 90% yield.

An enantioselective model synthesis of the 2,3-dihydro-1H-pyrrolo[1,2-a]indole core of the putative structure of yuremamine is reported in 39% overall yield and 96% ee over five steps. The model synthesis leverages enantioselective, rhodium-catalyzed hydroacylation of an N-vinylindole-2-carboxaldehyde as the key step in the installation of the stereochemical triad. An enantioselective synthesis of a densely functionalized dihydropyrroloindolone that maps onto the putative structure of yuremamine is demonstrated in 26% yield and 97% ee over eight steps.

Palladium-catalyzed conjugate addition of arylboronic acids to β,β-disubstituted enones in aqueous media is reported. Additions of a wide range of arylboronic acids to β,β-disubstituted enones occur to form ketone products bearing benzylic all-carbon quaternary centers. These reactions are promoted by a simple catalyst prepared from palladium trifluoracetate and 2,2′-bipyridine. The use of aqueous sodium trifluoracetate as the reaction medium significantly enhances reactivity and enables the formation of challenging bis-benzylic and ortho-substituted benzylic all-carbon quaternary centers.Keywords: aqueous media; arylboronic acid; conjugate addition; palladium; quaternary center

The development of a rhodium catalyst for endo- and enantioselective hydroacylation of ortho-allylbenzaldehydes is reported. A catalyst generated in situ from [Rh(COD)Cl]2, (R)-DTBM-SEGPHOS, and NaBARF promotes the desired hydroacylation reactions and minimizes the formation of byproducts from competitive alkene isomerization and ene/dehydration pathways. These rhodium-catalyzed processes generate the 3,4-dihydronaphthalen-1(2H)-one products in moderate-to-high yields (49–91%) with excellent enantioselectivities (96–99% ee).

Tandem reactions involving Rh-catalyzed intermolecular hydroacylations of alkynes with salicylaldehydes followed by intramolecular oxo-Michael additions are described for the diastereoselective synthesis of 2,3-disubstituted chroman-4-ones. The tandem hydroacylation/oxo-Michael additions occur to form 2,3-disubstituted chroman-4-ones in high yields from a range of 1,2-disubstituted acetylenes and substituted salicylaldehyes. The resulting 2,3-disubstituted chroman-4-ones are readily fluorinated to form trans-3-fluoro-2,3-disubstituted chroman-4-ones in high yields with excellent diastereoselectivity.

Catalytic, enantioselective hydroacylations of N-allylindole-2-carboxaldehydes and N-allylpyrrole-2-carboxaldehydes are reported. In contrast to many alkene hydroacylations that form six-membered rings, these annulative processes occur in the absence of ancillary functionality to stabilize the acylrhodium(III) hydride intermediate. The intramolecular hydroacylation reactions generate 7,8-dihydropyrido[1,2-a]indol-9(6H)ones and 6,7-dihydroindolizin-8(5H)-ones in moderate to high yields with excellent enantioselectivities.

We report catalytic, enantioselective intramolecular hydroacylation of N-vinylindole-2-carboxaldehydes. These hydroacylation reactions occur in the presence of a readily accessible rhodium catalyst and form chiral, non-racemic 2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-ones in high yields with excellent enantioselectivities.

Palladium-catalyzed N-tert-prenylations of indoles, tricarbonylchromium-activated indoles, and indolines that occur in high yields (up to 94%) with high tert-prenyl-to-n-prenyl selectivity (up to 12:1) are reported.

Catalytic, enantioselective 1,3-dipolar cycloadditions of nitrile imines with methyleneindolinones are reported. The spiro[pyrazolin-3,3′-oxindole] products are formed in good yields (up to 98%) and high enantioselectivity (up to 99% ee).

We report catalytic, intramolecular hydroacylations of N-allylimidazole-2-carboxaldehydes and N-allylbenzimidazole-2-carboxaldehydes. These exo-selective hydroacylations occur in the presence of a N-heterocyclic carbene catalyst to generate 5,6-dihydro-7H-pyrrolo[1,2-α]imidazol-7-ones and 1,2-dihydro-3H-benzo[d]pyrrolo[1,2-α]imidazol-2-ones in high yields (66–99%). In addition, hydroacylations of N-allylimidazole-2-carboxaldehydes in the presence of a chiral, non-racemic NHC catalyst occur, forming 5,6-dihydro-7H-pyrrolo[1,2-α]imidazol-7-ones in moderate-to-high yields (39–98%) with modest enantioselectivities (56–79% ee).

Catalytic, enantioselective [3 + 2] cycloadditions of azomethine ylides derived from alanine imino esters with 3-nitroindoles are reported. The dearomative cycloaddition reactions occur in the presence of a catalyst generated in situ from Cu(OTf)2 and (R)-Difluorphos to form exo′-pyrroloindoline cycloadducts and establish four contiguous stereogenic centers, two of which are fully substituted. The exo′-pyrroloindoline products are formed in moderate-to-good yields (39–85%) with high diastereoselectivities (up to 98:1:1 dr) and enantioselectivities (up to 96% ee).

This highlight discusses developments in transition metal-catalysed alkene and alkyne hydroacylation reactions over the past three years. The discussion summarizes the development of new catalyst systems for alkene and alkyne hydroacylation and applications to the synthesis of important ketone building blocks. The highlight captures transition metal-catalysed alkene and alkyne hydroacylation at a time of impressive growth when cobalt, nickel, ruthenium, and iridium catalysts are emerging as complements or replacements for traditional rhodium catalysts.

We report catalytic, enantioselective intramolecular hydroacylation of N-vinylindole-2-carboxaldehydes. These hydroacylation reactions occur in the presence of a readily accessible rhodium catalyst and form chiral, non-racemic 2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-ones in high yields with excellent enantioselectivities.

Catalytic, enantioselective 1,3-dipolar cycloadditions of nitrile imines with methyleneindolinones are reported. The spiro[pyrazolin-3,3′-oxindole] products are formed in good yields (up to 98%) and high enantioselectivity (up to 99% ee).