An Enantiocontrolled Formal Total Synthesis of (+)-Ipomeamarone, (-)-Ngaione, and Their Epimers

Abstract

A concise enantiocontrolled synthesis of (+)-(5S, 2R)- and (+)-(5R, 2R)-5-(3-furyl)-2-iodomethyl-2-methyloxolanes, (6) and (5), was achieved starting from (+)-(R)-2-hydroxymethyl-2-methylcyclobutanone (11) which was efficiently prepared by the tandem asymmetric epoxidation and 1,2-rearrangement of 2-cyclopropylidenepropanol (9). This constitutes an enantiocontrolled formal total synthesis of (+)-ipomeamarone (1), (+)-epiipomeamarone (2), (-)-ngaione (3) and its epimer (4)