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-tetralones are isolated from amino alcohol-mediated asymmetric domino reactions of α-disubstituted ketones, β-ketoesters, enol carbonates, α,β-unsaturated ketones, a silyl enol ether, or a β-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.

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