S. Fernandez et al., SELECTIVE ACYLATION OF A-RING PRECURSORS OF VITAMIN-D USING ENZYMES IN ORGANIC-SOLVENTS, Journal of organic chemistry, 60(19), 1995, pp. 6057-6061
Whereas Chromobacterium viscosum lipase (CVL) catalyzes selectively th
e acylation of the C-5 hydroxyl of the three stereoisomeric vitamin D
A-ring precursors 2a, 3a and 3b, only the C-3 hydroxyl of the fourth s
tereoisomer 2b is acylated under the same conditions in organic solven
t. In a convenient application, the racemic vitamin D A-ring precursor
4, possessing only the C-5 hydroxyl, was resolved using suitable cond
itions identified from the studies of 2 and 3.