Biosynthesis of α-cyclopiazonic acid: stereochemical aspects of D-ring formation
Abstract
(3R)-Mevalonic acid lactone is incorporated into α-cyclopiazonic acid with retention of the 4-pro-R-hydrogen atom; [1,2-13C2]acetate has been used as a probe to show that the cyclization of β-cyclopiazonic acid into α-cyclopiazonic acid involves a syn addition to the double bond.