The Reaction of Phosphoryl Chlorides with Enamines - A New Approach to β-Ketophosphonates

Abstract

Several approaches are available for the preparation of β-ketophosphonate esters. A Michaelis-Arbuzov approach using the reaction of an α-halo ketone with a trialkyl phosphite may in certain instances be controlled to favor the preparation of the target materials. However, an alternative pathway leading to the formation of vinyl phosphate esters often predominates. (This reaction system has recently been reviewed by Borowitz and Borowitz.¹) An alternative approach is that developed in recent years by Wiemer, et al.² involving the rearrangement of vinyl phosphate esters to the β-ketophosphonates.