SITE-SELECTIVE HYDROXYLATION OF STEROIDS VIA OXOMETALLOPORPHINATES COVALENTLY LINKED TO RING-D - INTRODUCTION OF HYDROXYL-GROUPS INTO THE C(9) AND C(12) POSITION OF 5-ALPHA-ANDROSTANES
Oxidation of synthetic manganese(III) porphyrins attached to steroidal substrates at C(17) (cf. 2 and 3) gives rise to hydrogen atom abstraction at C(9) and/or C(12), thereby leading to hydroxyl incorporation at these sites. The use of more robust metalloporphyrins (cf. 9) results in substantial increases in the yields of hydroxylated 5-alpha-androstanes.