Steroids Part VIII, boron trifluoride-catalysed rearrangements of 5β-methyl-9,10-epoxy-steroids

✍ Scribed by I.G. Guest; B.A. Marples

• Publisher: Elsevier Science
• Year: 1969
• Tongue: French
• Weight: 174 KB
• Volume: 10
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)88453-7

✦ Synopsis

Ihe boron triflucride catalysed rearrangements of steroidal epcxides have been widely reported (1). Recently, considerable interest has been shown in the backbone rearrangement of 4,5-and 5,6-epoxy-steroids (1). In an attempt to elucidate the mechanism of these rearrangements in more detail, we have studied the previously unreported reactions of the 5$-methyl-9,10epcxides (II) and (III) with bcrcn triflucride etherate. The mixed epcxides (II) and (III), prepared by moncperyhthalic acid oxidation of the 0 g(lO)-methcqy-acetate (I)(2) , were separated by preparative t.1.c. on silica gel. Treatment of a benzene solution of the a-epoxide (II) m.p. 86-87',[alD+ 10.5'(c**, 1.2) with boron triflucride etherate in benzene (7 min.) gave the rearranged diene (IV) (56$)[alD+ 67' (c, 1.1