Copper-catalyzed remote nucleophilic substitution of 5-ethynylthiophene esters

Abstract

Here we demonstrate a strategy for the copper-catalyzed nucleophilic substitution of 5-ethynylthiophene esters at ε-position. The key to the success lies in the design of an ethynyl group at the...

Copper-Catalyzed Remote Asymmetric Yne-Allylic Substitution of Yne-Allylic Esters with Anthrones

“…It has been well-established that a copper allenylidene complex is formed in situ as the key reactive intermediate, which can be trapped by various nucleophilic reagents at the γ position to furnish chiral terminal alkynes. − Copper-catalyzed asymmetric propargyl substitution of anthrones with propargylic esters was proven to be feasible . Recently, a new copper–vinylvinylidene complex was reported by Fang, He, Xu, our group, and other groups, which is formed in the presence of an extended CC bond or aryl group assembled on propargylic alcohol derivatives (Scheme c). A series of enantioenriched 1,3-enyne or 1,4-enyne products can be obtained with the regio- and enantioselective addition of the nucleophile to the ε or γ position of the copper-vinylvinylidene complex.…”