Highly Enantioselective Homoaldol Additions with Chiral N ‐Allylureas—Application to the Synthesis of Optically Pure γ‐Lactones

Numerous lactones are important pheromones, olfactories, or chiral synthetic building blocks. The enantioselective synthesis of lactones of the type 3 has now been accomplished using the readily accessible chiral allyltitanium compounds 1 and ent ‐ 1 by successive addition to aldehydes and ketones, acid hydrolysis, and oxidation.