SYNTHESIS OF ALKENES FROM KETONES VIA ARYLSULPHONYL - HYDRAZONES; MECHANISTIC VIEWS; THE ORGANIC CHEMISTR Y NOTEBOOK SERIES, A DIDACTICAL APPROACH, Nº 7

Abstract

This is the seventh chapter in the series published by the same authors: Organic Chemistry Notebook Series, a Didactical Approach. The aim of this series of studies is to help students to have a graphical view of organic synthesis reactions of diverse nature. Here we describe the mechanistic views of the synthesis of alkenes from ketones via arylsulphonylhydrazones. These methods employ aliphatic and alicyclic ketones with one a-hydrogen, that react along with toluene-p-sulphonylhydrazones and two equivalents of an alkyl-lithium or lithium diisopropylamide. The mechanism views for the transformation of pinacolone into 3,3-dimethyl-1-butene are proposed. The formation of 3-phenylpropene using phenylacetone is explained step by step. An approach is made on the obtaining of alkenes from ketones using derived enol ethers or esters by means of reductive excision or by means of coupling with organocuprates. We have used various series of reactions reviewed by W. Carruthers in 'Some modern methods of organic synthesis', and we have proposed didactical and mechanistic views for them. This theme is included in the chapter Formation of carbon-carbon double bonds in the text mentioned above. Spanish title: Sintesis de alquenos a partir de cetonas via arilsulfonilhidrazonas; vistas mecanisticas; De la serie: El cuaderno de notas de quimica organica, un enfoque didactico, N°7.