Cyanide Ion Promoted Addition of Acyl Phosphonates to Ethyl Cyanoformate: Synthesis of Tertiary Carbinols via Tandem Carbon−Carbon Bond Formations

Abstract

New cyanation/phosphonate-phosphate rearrangement/C-acylation reactions of cyanophosphate anion with cyanoformate esters are described. Phase-transfer cocatalysts facilitate cyanide-catalyzed reactions between acyl phosphonates and cyanoformates to afford protected tertiary carbinol products in good to excellent yields (74-95%). Ethyl cyanoformate is used as a cyanide source and electrophile. The scope of the reaction was investigated by using a number of benzoyl and acyl phosphonates along with ethyl cyanoformate. Representative chemoselective reduction of the product 5a afforded ethyl 3-amino-2-hydroxy-2-phenylpropanoate (13) in good yield.