Palladium‐Catalyzed Addition of 1,3‐Diones to Ynamides: An Entry to Alkoxy‐Substituted Enamides

Abstract

Abstract A new metal‐catalyzed addition reaction of 1,3‐diketones to ynamides, which provides access to unprecedented alkoxy‐substituted enamides, is disclosed herein. A screening of catalytic systems showed that both a phosphapalladacycle and a cationic gold complex were capable of promoting this reaction rapidly and cleanly. The scope investigation revealed that variously substituted terminal ynamides and cyclic 1,3‐diones were well tolerated. The use of internal ynamides led to the formation of both E and Z isomers with low to good selectivities. The proposed mechanism suggests that the phosphapalladacycle acts as a π Lewis acid to activate the ynamide.