Lewis Acid Mediated Nazarov Cyclization as a Convergent and Enantioselective Entry to C-nor-D-homo-Steroids.

Abstract

A straightforward synthesis of C-nor-D-homo steroids starting from (+)-Wieland-Miescher ketone is reported. This convergent synthetic strategy utilizes ascalable diastereoselective Nazarov cyclization of functionalized chiral aryl vinyl ketones, allowing for further functionalization. The ability to conduct this key transformation on a multi-gram scale paves the way for the synthesis of a variety of completely new C-nor-D-homo steroids, without the need of a classic steran steroid rearrangement or achiral linear reaction sequences.