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Herein, we report the development of a method for highly regio‐, stereo‐, and enantioselective B−H bond insertion reactions of α‐silylcarbenes generated from 1‐silylcyclopropenes in the presence of a chiral copper(I)/bisoxazoline catalyst for the construction of chiral γ,γ‐disubstituted allylic gem‐silylboranes, which cannot be prepared by any other known methods. This reaction is the first highly enantioselective carbene insertion reaction of α‐silylcarbenes ever to be reported. The method shows general applicability for various 3,3‐disubstituted silylcyclopropenes and exclusively affords E‐products. The novel chiral γ,γ‐disubstituted allylic gem‐silylborane products are versatile allylic bimetallic reagents with high stability and have great synthetic potential, especially for the construction of complex molecules with continuous chiral centers. [ABSTRACT FROM AUTHOR]

The scarcity of reliable methods for synthesizing chiral gem‐diarylmethine borons limits their applications. Herein, we report a method for highly enantioselective dirhodium‐catalyzed B−H bond insertion reactions with diaryl diazomethanes as carbene precursors. These reactions afforded chiral gem‐diarylmethine borane compounds in high yield (up to 99 % yield), high activity (turnover numbers up to 14 300), high enantioselectivity (up to 99 % ee) and showed unprecedented broad functional group tolerance. The borane compounds synthesized by this method could be efficiently transformed into diaryl methanol, diaryl methyl amine, and triaryl methane derivatives with good stereospecificity. Mechanistic studies suggested that the borane adduct coordinated to the rhodium catalyst and thus interfered with decomposition of the diazomethane, and that insertion of a rhodium carbene (generated from the diaryl diazomethane) into the B−H bond was most likely the rate‐determining step. [ABSTRACT FROM AUTHOR]

The first highly enantioselective intramolecular N−H bond insertion was realized by using copper catalysts modified with chiral spirobisoxazoline ligands, which provides a novel strategy for the synthesis of chiral 2-carboxytetrahydroquinolines. This reaction features fast reaction rate, high yield, high enantioselectivity, and mild reaction conditions. [ABSTRACT FROM AUTHOR]

A highly enantioselective NH insertion reaction of α-diazoketones was developed by using cooperative catalysis by dirhodium(II) carboxylates and chiral spiro phosphoric acids. The insertion reaction provides a new access route to diverse chiral α-aminoketones, which are versatile building blocks in organic synthesis, with fast reaction rates, good yields and high enantioselectivity under mild and neutral conditions. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed asymmetric OH insertion reaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α-aryl-α-diazoacetates into the OH bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium-catalyzed asymmetric OH insertion reaction provided an efficient and highly enantioselective method for the preparation of synthetically useful optically active α-aryl-α-aryloxyacetates. [ABSTRACT FROM AUTHOR]

Efficient: A copper‐catalyzed enantioselective intramolecular insertion of carbenoids into phenolic OH bonds has been developed. This method can be used for the synthesis of the title compounds in high yields and excellent enantioselectivities under mild and neutral conditions (see scheme). NaBArF=sodium tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate. [ABSTRACT FROM AUTHOR]

An asymmetric carbenoid insertion into S–H bonds catalyzed by copper–chiral spiro bisoxazoline complexes has been developed, in which a series of α-mercaptoesters were produced in high yields with moderate to good enantioselectivities (up to 85% ee); this result represents the best enantioselectivity in the catalytic asymmetric carbenoid S–H bond insertion reaction. [ABSTRACT FROM AUTHOR]

The transition-metal-catalyzed reaction of diazo compounds with arenes or heteroarenes is an efficient and straightforward approach to functionalize aromatic compounds. This digest summarizes recent progresses on transition-metal-catalyzed asymmetric reactions of diazo compounds with electron-rich (hetero-) arenes, including C–H functionalization, cascade reaction, cyclopropanation, cycloaddition, Buchner reaction and intramolecular dearomatization. [ABSTRACT FROM AUTHOR]