Acylimidazolides as Versatile Synthetic Intermediates for the Preparation of Sterically Congested Amides and Ketones: A Practical Synthesis of Proscar®

Abstract
Acylimidazolides react with magnesium amides to produce car-boxamides in excellent yields, whereas Fe(III) catalyzed cross coupling between acylimidazolide and Grignard reagents produce ketones in high yields. These methods were utilized to prepare the α-reductase inhibitor Proscar® as well as various 17β-amide and ketone analogs of Δ1-4-aza-5α-androsten-3-one.