Amino alcohol-mediated enantioselective syntheses of α-substituted indanones and tetralones, ammonium enolates as key intermediates

Optically active 2-substituted-1-indanones or 2-substituted-1-tetraiones are isolated from amino alcohol-mediated asymmetric domino reactions of alpha-disubstituted ketones, beta-ketoesters, enol carbonates, alpha, beta-unsaturated ketones, a silyl enol ether, or a beta-ketoacid, with some of these reactions occurring under UV-light irradiation or Pd catalysis. The absence of a relationship between the nature of the substrate and the absolute configuration of the ketone produced is due to the protonation of a common ammonium enolate as the key enantioselective step. The enantioselectivity depends on various factors, which indicates the occurrence of side pathways. (C) 2014 Elsevier Ltd. All rights reserved.