Rhodium-Catalyzed Enantioselective Hydrosilylation of 1,1-Disubstituted Enamides.

Catalytic hydrosilylation of 1,1-disubstituted enamides is one of the most challenging and synthetically useful processes in organosilicon chemistry and asymmetric catalysis. Herein, we report a rhodium-catalyzed enantioselective hydrosilylation of α-arylenamides with substituted hydrosilanes with the aid of chiral P-ligand, including newly developed spirophosphite ligands, giving various chiral β-silylated amides in excellent yields with good to excellent enantioselectivities (98:2 er after recrystallization). In addition, chiral β-silylated amines can be obtained by further functionalization of the hydrosilylation product.

Solvent-Dependent Rhodium-Catalyzed Divergent Hydrofunctionalization of Trifluoromethylalkenes.

We report a rhodium-catalyzed anti-Markovnikov regioselective hydrosilylation of trifluoromethylalkenes with substituted silanes giving various α-trifluoromethyl-β-silanes in good to excellent yields. The hydrogenation products were obtained via the same key intermediate treated with methanol as a protic solvent. Both transformations had a broad functional tolerance and were expected to facilitate the construction of complex α-trifluoromethyl compounds.

Combined Dynamic Kinetic Resolution and C-H Functionalization for Facile Synthesis of Non-Biaryl-Atropisomer-Type Axially Chiral Organosilanes.

Although asymmetric C-H functionalization has been available for the synthesis of structurally diverse molecules, catalytic dynamic kinetic resolution (DKR) approaches to change racemic stereogenic axes remain synthetic challenges in this field. Here, a concise palladium-catalyzed DKR was combined with C-H functionalization involving olefination and alkynylation for the highly efficient synthesis of non-biaryl-atropisomer-type (NBA) axially chiral oragnosilanes. The chemistry proceeded through two different and distinct DKR: first, an atroposelective C-H olefination or alkynylation produced axially chiral vinylsilanes or alkynylsilanes as a new family of non-biaryl atropisomers (NBA), and second, the extension of this DKR strategy to twofold o,o'-C-H functionalization led to the multifunctional axially chiral organosilicon compounds with up to >99 % ee.