Utilization of Aldoses as a Carbonyl Source in Cyclocarbonylation of Enynes

Abstract

The reaction of enynes with acetyl-masked aldoses in the presence of a rhodium(I) catalyst resulted in cyclocarbonylation, thus avoiding the direct use of carbon monoxide, to afford bicyclic cyclopentenones. In rhodium catalysis, aldoses serve as a carbon monoxide equivalent by donating their carbonyl moieties on the acyclic aldehyde form to enynes. A variety of aldoses, including d-glucose, d-mannose, d-galactose, d-xylose, and d-ribose, can be used as a carbonyl source. Using the method, a wide variety of enynes were cyclocarbonylated in 22−67% yields. An asymmetric variant also proceeded with moderate to high enantioselectivity