PhINSes mediated aziridination of 11-pregnane derivatives: synthesis of an 11,12-aziridino analogue of neuroactive steroids

Reaction of 11-pregnene-3,20-dione () or 3-α-acetoxy-11-pregnen-20-one () with trimethylsilylethanesulfonyl (‘Ses’) iminoiodinane in the presence of copper (I) triflate gave the corresponding α,α-11,12-aziridino steroids and in 53 and 45% yields, respectively. The Ses group of each compound was removed using the TASF reagent and the resulting free aziridine NH was methylated to afford the 11α,12α-N-methyl aziridinosteroids and , respectively. The latter is a conformationally constrained analogue of the endogenous neurosteroid pregnanolone ().