Infrared Spectra and Structure Of Carbanions ‐ XIV. Isomeric Carbanionic Adducts of Some Substituted Cyano‐Polyenes

Abstract

It was found on the basis of IR spectroscopic data, that the nucleophilic CH 0-attack to substituted cyano-butadienes COOEt , C H NO -p) and 1-cyano-1-ethoxycarbonyl-6-phenyl-hexatriene takes place at the fi -carbon atom. The 1,2-carbanionic adducts , thus formed, isomerise spontaneously into the thermodynamically more stable 1,4-adducts of the butadiene derivatives and 1,6-adduct of the studied hexatriene.The reaction of sodium methoxide with a great number of cyano-ethylene8 2 in dimethyl sulphoxide (DMSO) results in the formation of carbanionic adducts; their structure was established the methoxy group is bonded to the /3 -carbon atom and the negative charge is delocalized over the cyanornethide fragment (Formula 1).