α-Metalated isocyanides in organic synthesis

Abstract

α-Alkali-metalated isocyanides, which can be obtained from isocyanides and bases, are both nucleophilic and electrophilic. They can add to polar double bonds, forming heterocycles. They are also synthons for α-metalated primary amines. This paper describes their use in organic synthesis: 1) In heterocyclic synthesis to gives 2-oxazolines, 2-thiazolines, 2-imidazolines, pyrroles, oxazoles, thiazoles, 2-imidazolin-5-ones, 1,3-oxazines and -thiazines. 2) In the field of formylaminomethylenation, transformation of ketones and aldehydes with alkyl isocyanoacetate to formylamino acrylic esters and chain lengthening of ketones to carboxylic acids or carbonitriles with tosyl methylisocyanide. 3) In connection with their use as synthons for primary amines it is demonstrated how they may be used for preparation of 1,2- and 1,3-amino alcohols, 2,3-diaminoalkanoic acids and for synthesis of amino acids.