Unexpected ring contraction of 1-aryl-cyclohexa-2,5-dienes under palladium catalysis

Abstract

The reaction of 1,1-disubstituted cyclohexa-2,5-dienes with aryl iodides in the presence of Pd (0) unexpectedly provided bicyclo[3.1.0] compounds in a very diastereocontrolled fashion in moderate to good yield. A tentative mechanism is proposed to rationalize this unusual reactivity of cyclohexadienes under palladium catalysis.