Copper(II)-catalyzed Domino Reaction of the Acyclic Ketene-(S,S)-Acetals with Diazo Compounds: Convenient Synthesis of Poly-substituted Thiophenes

Copper(II)-catalyzed domino reaction between the acyclic ketene-(S,S)-acetals and diazo compounds has been successfully developed. This reaction proceeds through a sequential formation of electrophilic copper carbenoid, sulfur ylide and subsequent C-S bond coupling and cleavage. Notably, the domino reaction features broad the readily available acyclic ketene-(S,S)-acetals scope and provides a new strategy for the synthesis of poly-substituted thiophenes.