Copper‐Catalyzed Enantioselective Sonogashira Type Coupling of Alkynes with α‐Bromoamides

Abstract

An asymmetric copper-catalyzed Sonogashira type coupling between alkynes and a-bromoamides has been developed. This method represents a facile approach to synthetically useful b, g-alkynyl amides from two readily available starting materials in a highly enantioselective manner. A Bisoxazoline diphenylanaline (BOPA) serves as the effective chiral ligand. Preliminary mechanistic studies support the formation of alkyl radical species. Scheme 1. The synthesis of a-alkynyl carbonyl compounds.

Copper‐Catalyzed Thiolation of Terminal Alkynes with N‐Thiosuccinimides to Access Alkynyl Sulfides

“…It seemed that the potential disulfide or thiol intermediate, which might be derived from the self‐metathesis or decomposition of N ‐thiosuccinimide 2 b , was not involved in the catalytic system. In order to probe the role of copper catalyst in the thiolation, a stoichiometric amount of copper acetylide 8 [18] was prepared and subjected to the reaction without copper catalyst. As a result, 3 ab was obtained in 87 % yield, indicating that 8 is the key intermediate in this transformation.…”

“…By the way, we also investigated the influence of different solvents. Strong polar solvents gave better performance than weak polar or nonpolar solvents (entries [18][19][20][21][22]. And the reaction proceeded equally well under Ar atmosphere (entry 23).…”

Copper-catalyzed Sonogashira reactions: advances and perspectives since 2014

“…Mo et al proposed enantioselective Sonogashira type coupling of alkynes with α-bromoamides catalyzed by copper. 25 This reaction enabled the enantioselective coupling between α-halo amides with unfunctionalized terminal alkynes and as a result β,γ-alkynyl amides were generated. This is a simple method for synthesising synthetically valuable alkynyl amides from two widely available starting materials in a highly enantioselective way.…”