Enantioselective Reduction of Benzofuranyl Aryl Ketones.

Enantioselective transfer hydrogenation of benzofuranyl aryl ketones proceeds with moderate to good enantioselectivity even when the aryl group is not sterically differentiated by <italic>ortho</italic>-substituents. The best results are obtained with substrates that are functionalised by electron-withdrawing aryl groups that contrast with the electron-rich benzofuran, which is consistent with [Ru-ArC-H]˙Ar π interactions acting as a control element. Enantioselective pressure hydrogenation gives lower enantioselectivity irrespective of electronic effects, unless the aryl group is <italic>ortho</italic>-substituted, in which case up to 86% ee can be realised. [ABSTRACT FROM AUTHOR]