Expanding Blaise‐Type Reactions towards Indium‐Mediated Transformations of α‐Bromo‐β‐keto Esters with Nitriles

Abstract

The aim of this work is the identification of mild reaction conditions for the Blaise‐type transformation of brominated β‐keto esters with nitriles to generate enamino‐substituted keto esters. The best results were obtained when a combination of indium metal (0.7 equiv.) with indium trichloride (1.6 equiv.) were applied at 60 °C for 20 to 72 hours, and these conditions could be applied to a broad range of nitriles and a significant number of different β‐keto esters. The transformation of aliphatic nitriles proved to be difficult and gave only moderate yields. However, aromatic nitriles gave good yields in many cases. The applicability range of β‐keto esters is acceptable while some electron‐deficient aryl‐substituents on the keto ester were challenging substrates. Nevertheless, we were able to expand the scope of the Blaise‐type reaction towards brominated β‐keto esters significantly.