Copper-Catalyzed Three-Component Reactions: Access to Furan Derivatives

Significance

The authors previously reported that alcoholic oxonium ylides generated in situ from diazo compounds and alcohols in the presence of Rh₂(OAc)₄ can be trapped by aldehydes and imines. In this report, copper complexes were shown to be superior catalysts (in terms of yield and cost) in the stereoselective three-component reactions of aryl diazoacetates, alcohols, and chalcones for constructing γ-hydroxy ketone derivatives 1. Good yields and excellent syn/anti selectivities were achieved with Cu(OTf)₂. Furthermore, the reaction can be scaled up to multigram quantities by using cheaper CuSO₄ as catalyst.