Face selectivity in the reduction with dideuteriodi-imide of endoperoxides derived from the singlet oxygenation of cycloalka-1,3-dienes

Abstract

Four dioxabicyclo[n.2.2]alkenes (n= 1–4) have been reduced with dideuteriodi-imide. For each reduction, the ratio of the amount of product arising from cis-addition of two deuterium atoms to the face of the double bond syn to the dioxygen bridge to that arising from addition to the anti face has been determined by ¹H-decoupled ²H n.m.r. spectroscopy, and the structures of the individual isomers have been determined by ¹H n.m.r. spectroscopy. The cyclopentadiene endoperoxide (n= 1) yields exclusively the anti-isomer, whereas the cyclohexadiene endoperoxide (n= 2) affords a mixture containing 66% of syn isomer, and the cycloheptadiene and cyclo-octadiene endoperoxides (n= 3 and 4) give only the syn-isomer. The results are consistent with the expected variation across the series in both electronic and steric effects.