Synthesis of (20S)-[7,7,21,21-2H4]-3β-(tert-butyldimethylsilanyloxy)-20-methyl-pregn-5-en-21-ol, a useful intermediate for the preparation of deuterated isotopomers of sterols
ethyl (20S)-3beta-(tert-butyldimethylsilanyloxy)-7-oxo-pregn-5-en-20-carboxylate. Using controlled experimental conditions, it has also been shown that the dichloroaluminum hydride reduction of a 7-ketosteroid affords the corresponding 7beta-hydroxy derivative in a highly stereoselective manner.