M. Ihara et al., RADICAL CYCLIZATION WITH HIGH DIASTEREOFACIAL SELECTIVITY - ASYMMETRIC-SYNTHESIS OF (-12B-EPIDEVINYLANTIRHINE()), Journal of the Chemical Society. Perkin transactions. I, (7), 1997, pp. 991-992
Radical cyclisation of the chiral alpha,beta-unsaturated ester 1, carr
ied out in the presence of MAD, gives six-membered cyclic acetal 2 dia
stereoselectively, which is transformed into(+)-12b-epidevinylantirhin
e 7.