Rhodium-Catalyzed Parallel Kinetic Resolution of Racemic Internal Allenes Towards Enantiopure Allylic 1,3-Diketones

A rare case of a parallel kinetic resolution of racemic 1,3- disubstituted allenes by means of a rhodium- catalyzed addition to 1,3- diketones furnishing enantiopure allylic 1,3diketones is described. Mechanistic experiments demonstrate that the different allene enantiomers react in parallel to either the diastereomeric E- or Z- allylic 1,3- diketones with the same absolute configuration of the newly formed stereogenic center. A broad substrate scope demonstrates the synthetic utility of this new method.