Direct Catalytic Asymmetric <i>Enolexo</i> Aldolizations

Abstract

32 years after the first, and still the only, catalytic asymmetric intramolecular aldol reaction was published in this journal, the proline-catalyzed Hajos–Parrish–Eder–Sauer–Wiechert reaction is extended for the first time to catalytic asymmetric enolexo aldolizations. The process provides substituted cyclohexanes in excellent diastereo- and enantioselectivities. For example, heptanedial is converted into the corresponding cyclic anti-configured aldol in 99 % ee (see scheme).