Zy. Liu et al., NATURAL-PRODUCTS SYNTHESIS BY RETRO-DIELS -ALDER REACTION .14. STEREOSPECIFIC SYNTHESIS OF (+ -)-EPOFORMIN AND (+/-)-EPIEPOFORMIN/, Huaxue xuebao, 55(6), 1997, pp. 611-616
p - Benzoquinone reacted with cyclopentadiene to mask its double bond.
After introduction of the necessary functional groups and substituent
, retro Diels - Alder reaction gave (+/-) - epiepoformin, which was co
nverted into (+/-) - epoformin by inversion of its hydroxy configurati
on in 70% and 65% overall yields, respectively.