Stereoselective Synthesis of 2Z,4E-Configured Dienoates through Tethered Ring Closing Metathesis

摘要

A two-step sequence leading from racemic allylic alcohols and vinylacetic acid to ethyl (2Z,4E)-dienoatesis described. The sequence involves Steglich esterification of the reactants, followed by a one-pot ring closing metathesis-base induced elimination-alkylation reaction to furnish the products in high stereoselectivity. Trapping of the intermediate sodium carboxylates is accomplished efficiently using Meerwein's salt Et3OBF4.