Rh-Catalyzed Reaction of Propargylic Alcohols with Aryl Boronic Acids-Switch from β-OH Elimination to Protodemetalation

摘要

It is known that Rh-catalyzed reaction of propargylic alcohols with aryl metallic reagents undergoes SN2'-type reaction affording allenes via a sequential arylmetalation and β-OH elimination process.Here we report a Rh/Ag-cocatalyzed reaction of propargylic alcohols with organoboronic acids affording stereo-defined (E)-3-arylallylic alcohols via arylmetalation and protodemetalation with a high regioand stereoselectivity under very mild conditions.The reaction exhibits a good substrate scope and the compatibility with synthetically useful functional groups with no racemization for optically active propargylic alcohols.Such a reaction may also be extended to homopropargylic alcohols with a remarkable regioselectivity and exclusive E-stereoselectivity.