An operationally simple, one-pot synthetic protocol for the formation of all-carbon, highly substituted five- and six-membered rings is described. In this two-step procedure, an asymmetric allylic alkylation (AAA) of Morita-Baylis-Hillman (MBH) carbonates with allylmalononitrile, catalyzed by a chiral tertiary amine, is followed by a ring-closing alkene metathesis (RCM) reaction.
Products are obtained in high yields, and an excellent level of optical purity of some of the target compounds is achieved after just a single recrystallization.