Mechanistic switch leading to highly efficient chirality transfer in Pd(0)-catalyzed coupling-cyclization of aryl iodides with 1:1 acid-base salts of 2,3-allenoic acids and L-(-)-cinchonidine or D-(+)-/L-(-)-alpha-methylbenzylamine. Enantioselective synthesis of highly optically active 3-aryl polysubstituted butenolides.

An efficient methodology provides an easy access to highly optically active polysubstituted butenolides starting from aryl halides and 1:1:salts of optically active 2,3-allenoic acid-base via an oxidative addition-coordinative cyclization-reductive elimination mechanism, which led to the high efficiency of this chirality isomerization reaction.