Copper(ii)-catalyzed stereoselective 1,2-addition vs. Ferrier glycosylation of “armed” and “disarmed” glycal donors

The thermodynamic–kinetic switch model enables the selective activation of the enol–ether moiety in “armed” and “disarmed” glycal donors leading to syn-diastereoselective direct addition or an allylic rearrangement.

Efficient Synthesis of a 5α-Reductase Inhibitor, 3-(Tetrazol-5-yl)-3,5-pregnadien-20-one through Allylic Rearrangement of Cyanophosphates

We describe the use of allylic rearrangements of cyanophosphates for the efficient and practical synthesis of 3-(tetrazol-5-yl)-3,5-pregnadien-20-one, which is a potent 5α-reductase inhibitor (IC50: 15.6 nM), from pregnene-3,20-dione in 92% overall yield in four steps.