A new method for the preparation of ent-cholesterol from ent-testosterone

An efficient total synthesis of the enantiomer of cholesterol is reported. The enantiomer of testosterone was prepared and converted into a C-21 3-sil yloxy-Delta(5,17(20))-diene according to literature procedures. The additio nal five carbon atoms of the cholesterol side chain were introduced by an e ne reaction. Selective hydrogenation of the resultant Delta(16) double bond and removal of the 22-hydroxyl group by a mesylation and demesylation sequ ence gave ent-cholesterol in 9.7% overall yield from ent-testosterone (C) 1 999 Elsevier Science Ltd. All rights reserved.