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We report an organocatalyst that combines a triazolium N-heterocyclic carbene (NHC) with a squaramide as a hydrogen-bonding donor (HBD), which can effectively catalyze the atroposelective ring-opening of biaryl lactams via a unique amide C–N bond cleavage mode. The free carbene species attacks the amide carbonyl, forming an axially chiral acyl-azolium intermediate. Various axially chiral biaryl amines can be accessed by this methodology with up to 99% ee and 99% yield. By using mercaptan as a catalyst turnover agent, the resulting thioester synthon can be transformed into several interesting atropisomers. Both control experiments and theoretical calculations reveal the crucial role of the hybrid NHC-HBD skeleton, which activates the amide via H-bonding and brings it spatially close to the carbene centre. This discovery illustrates the potential of the NHC-HBD chimera and demonstrates a complementary strategy for amide bond activation and manipulation. Developing efficient methods for the formation and cleavage of amide species is a primary research goal, but the amide C–N bond cleavage is exceptionally challenging. Here, the authors report the development of an organocatalyst that can effectively catalyze the atroposelective ring-opening of biaryl lactams via amide C–N bond cleavage. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Alkynes are one of the most significant functional groups in organic chemistry and great efforts have been made to explore efficient approach for the construction of chiral alkynes. The asymmetric C(sp3)–C(sp) cross‐coupling provides a significant complementary strategy through radical‐initiated process. However, the stereocontrol of highly reactive and unstable radical intermediate has been a challenge for decades. To address this problem, a variety of chiral ligands are developed for initiating the reaction and achieving enantiocontrol of alkyl radicals. This review summarizes recent developments in copper‐catalyzed enantioselective alkynylation of prochiral alkyl radicals and their brief mechanistic studies. [ABSTRACT FROM AUTHOR]

A catalytic asymmetric alkylation of azoles with secondary 1‐arylalkyl bromides through direct C−H functionalization is reported. Under blue‐light photoexcitation, a copper(I)/carbazole‐based bisoxazoline (CbzBox) catalytic system exhibits good reactivity and high stereoselectivity, thus offering an efficient strategy for the construction of chiral alkyl azoles. These reactions proceed at low temperature and are compatible with a wide range of azoles. [ABSTRACT FROM AUTHOR]

A method for remote radical C-H alkynylation and amination of diverse aliphatic alcohols has been developed. The reaction features a copper nucleophile complex formed in situ as a photocatalyst, which reduces the silicon-tethered aliphatic iodide to an alkyl radical to initiate 1, n -hydrogen atom transfer. Unactivated secondary and tertiary C-H bonds at β, γ, and δ positions can be functionalized in a predictable manner., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A catalytic asymmetric alkylation of azoles with secondary 1-arylalkyl bromides through direct C-H functionalization is reported. Under blue-light photoexcitation, a copper(I)/carbazole-based bisoxazoline (CbzBox) catalytic system exhibits good reactivity and high stereoselectivity, thus offering an efficient strategy for the construction of chiral alkyl azoles. These reactions proceed at low temperature and are compatible with a wide range of azoles., (© 2020 Wiley-VCH GmbH.)