Reduction of triterpenoid ketones with bornan-2-exo-yloxyaluminium dichloride: a convenient preparation of axial triterpene alcohols
Abstract
Reduction of 3-oxo-triterpenoids with bornan-2-exo-yloxyaluminium dichloride furnishes axial (3α-) alcohols as the major products (75–100%), which are easily separable from the reaction mixtures. Reduction with sodium borohydride gives mainly the 3β-alcohols (85–95%).