First one-pot organocatalytic synthesis of α-methylene-γ-lactones

摘要

All in one pot: an organocatalytic highly enantioselective synthesis of α-methylene-γ-lactones has been reported. The reaction between protected 2-hydroxymalonates and MBH carbonates is simply catalysed by chiral Lewis bases affording after acid treatment the corresponding lactones in excellent yields and enantioselectivities. The a-methylene-γ-lactone motif is a key structural element found in a vast number of biologically significant natural products, mainly of the Compositae family. The first α-methylene-γ-lactones were isolated over 100 years ago and were often used in traditional medicine for the treatment of inflammatory diseases. In recent years these compounds have been found to possess a broad spectrum of biological activities ranging from antimicrobial, antifungal, phytotoxic to cytotoxic/anti-cancer.