Three-Component Cascade Bis-heteroannulation of Aryl or Vinyl Methylketoxime Acetates toward Thieno[3,2-c]isoquinolines

A three-component cascade bis-heteroannulation reaction is described that provides access to a variety of benzo[4,5]thieno[3,2-c]isoquinoline and thieno[3,2-c]isoquinoline compounds from easily available methylketoximes, o-halobenzaldehydes, and elemental sulfur. Mechanistic studies reveal a two-step process involving a sequential copper and sulfur catalysis relay.