Jt. Kohrt et al., HIGHLY FUNCTIONALIZED CYCLOHEXENYL SYSTEMS - ENZYMATIC RESOLUTION ANDSELECTIVE OXIRANE OPENING REACTIONS OF P-BENZOQUINONE DERIVATIVES, Journal of organic chemistry, 63(15), 1998, pp. 5088-5093
Diol 2, derived in two steps from p-benzoquinone, was converted to epo
xy alcohol 3. The latter was resolved with crude Candida rugosa lipase
in isopropenyl acetate/toluene to give acetate (-)-4 and residual alc
ohol (+)-3. Oxirane ring opening reactions of 3 and the corresponding
acetate and TBDMS derivatives with a variety of nucleophiles gave dias
tereomerically pure 3,4,5,6-tetrasubstituted cyclohexene derivatives o
f type 6. X-ray crystal structures were obtained on compounds 6e, 6m a
nd the diacetate prepared from 6l. Nitrogen nucleophiles provided entr
y in various aziridines 10. Pd(0)-catalyzed nucleophilic additions to
substrate 5 cleanly provided the diastereomeric pattern of type 11. tr
ans-5,6-Disubstituted cyclohexadienes 13 were obtained by an unusual s
yn-reductive elimination on bromocarbonates 12 utilizing Pd or Zn.