Diastereoselective Catalytic MPV Reduction

Abstract

Catalytic Meerwein-Ponndorf-Verley reduction of protected α-amino aromatic ketones gave protected ephedrine and its analogues in good to excellent yields and excellent diaste­reoselectivities. The reduction proceeds via a chelating transition state to give the anti product. Under the same conditions, the catalytic MPV reduction of α-alkoxy ketones afforded syn-α-alkoxy alcohols in excellent yield and good diastereoselectivity. A Felkin-Anh transition state is proposed to explain the diastereoselectivity observed.