Applications of homoallylic alcohols derived from (-)-sparteine-mediated asymmetric homoaldolization: Entry to 5-to 8-membered unsaturated oxacycles through metathesis reaction

A series of enantioenriched 4-hydroxy-1-alkenyl carbamates was prepared by (-)-sparteine-mediated homoaldolization. These were transformed into unsatu rated oxacycles, involving simple synthetic transformations, with ring-clos ing metathesis (RCM) as the key step.