DBU‐Catalyzed Glutamation of Phenols, Thiophenols, Secondary Amines and Imides

Abstract

1,8‐Diazabicyclo[5.4.0]undec‐7‐ene (DBU) catalyzed Michael additions between α,β‐unsaturated esters and benzophenone‐imine of glycine esters in THF at room temperature by using LiBr as an additive for glutamation of phenols, thiophenols, secondary amines and imides have been realized. 3‐Substituted glutamic acid esters were obtained in excellent yields and diastereoselectivities (up to quant. yield and > 20:1 d.r.). These glutamic acid esters were easily converted into their corresponding pyroglutamic acid esters in high yields through acidic hydrolysis followed lactamation.