Aza Steroids .7. Synthesis Of Ring A-Oxygenated 6-Aza Steroids

Selective hydroboration of N-benzyl-6-aza-2,4-cholestadien-7-one (III) provided the two isomeric 3-hydroxy-6-aza steroids (V and VI) and the 2α-hydroxyderivative IV. This sequence provides a general entry into ring A-oxygenated 6-aza steroids and provides the first examples of this series which bear the Δ 4 -3-keto chromophore.