Asymmetric syntheses of isostegane derivatives using trivalent iodine reagents

Abstract

Two asymmetric syntheses of the isostegane derivative (+)-3 are reported, both involving oxidation of a homochira1 2,3-dibenzylbutyrolactone with phenyliodonium bis(trifluoroacetate). Of particular interest is the fact that the oxidative step can be carried out directly on a precursor containing a hemiacetal functional group and leads to the same configuration of the biaryl unit.