Recent Applications of α‐Metalated Isocyanides in Organic Synthesis

Abstract

AbstractBeing both nucleophilic and electrophilic, α‐metalated isocyanides can add to polar double bonds, forming heterocycles. They are also synthons for α‐metalated primary amines. This article describes recent or improved procedures for their use in organic synthesis: (1) In heterocyclic syntheses to give 2‐oxazolines, 2‐imidazolines, 2‐thiazolines, oxazoles and oligooxazoles, thiazoles, triazoles, imidazolinones, pyrroles, 5,6‐dihydro‐1,3‐oxazines and ‐thiazines, and (via cycloaddition with nitrones) 2‐imidazolidinones. (2) In the field of formylaminomethylenation, for example transformation of estrone methyl ether and a keto sugar into the corresponding α‐formylaminoacrylic esters, and the conversion of aldehydes and ketones by 3‐ and 4‐pyridyl‐methyl isocyanides into N‐(1‐pyridyl‐1‐alkenyl)formamides and their hydrolysis to 3‐ and 4‐acylpyridines. (3) In connection with the use of α‐metalated isocyanides as synthons for α‐metalated primary amines, the author demonstrates how they may be used for preparation of 1,2‐ and 1,3‐amino alcohols, 1,2‐diamines, 2,3‐diaminoalkanoic acids and for synthesis of higher amino acids starting from simple amino acids.