Organocatalyzed enantio- and diastereoselective isomerization of prochiral 1,3-cyclohexanediones into nonalactones bearing distant stereocenters.

ABSTRACT

The lactonization of 2-(2-nitrophenyl)-1,3-cyclohexanediones containing an alcohol side chain and up to three distant prochiral elements is reported by isomerization under the mediation of simple organocatalysts such as quinidine. Through a process of ring expansion, strained nonalactones and decalactone are produced with up to three stereocenters in high er and dr (up to 99 1). Distant groups, including alkyl, aryl, carboxylate and carboxamide moieties, were examined.