β-Lactones as Key Building Blocks: Synthetic Applications to Diverse Natural Products

Abstract

A history and detailed account of the applications of β-lactones towards natural products and bioactive compounds in the last ten years is discussed as these small heterocycles are becoming more widely recognized for their reactivity, numerous methods of construct, and high degree of functionalization.

An improvement to the nucleophile catalyzed aldol-β-lactonization of keto-acids is reported employing commodity reagents delivering gram quantities of bicyclic β-lactone.

The first total synthesis of caulolactone A is reported employing a highly diastereoselective biscyclization to a key carvone–derived β-lactone. The natural product was completed from chiral pool (R)-carvone in 10 total steps.

Towards rapidly generating complex cyclopentanes an organocatalyzed tandem Michael aldol-lactonization process is reported. Subsequently revealing conditions for an enantioselective variant generating two C-C bonds, one C-O bond, two rings, and up to three contiguous stereocenters from simple starting materials.