Catalytic enantioselective synthesis of α-allyl-α-aryl 1-indanones via palladium-catalysed decarboxylative asymmetric allylic alkylation

Herein, we describe an efficient catalytic enantioselective synthesis of a variety of α-allyl-α-aryl 1-indanones. All carbon quaternary stereocentres bearing a variety of substituted aryl groups were accessed in moderate to excellent yields up to 94 %. The enantioselectivities of the products were heavily dependent on the stereoelectronic properties of the aryl group and substitution of the indanone moiety. Excellent ees of up to 97 % were obtained with the sterically hindered di-ortho substituted arenes. In an attempt to explain the selectivities obtained, the role of the aryl moiety in the transition state was investigated using variable temperature NMR spectroscopy. The results led to further development of our current stereochemical rationale for the allylation of α-aryl containing substrates.