Reaction of copper enolates of esters with propargylic systems. Facile preparation of 3, 4-dienoic esters, stereoselective rearrangement to (2E, 4Z)-and (2E, 4E)- …

RA Amos, JA Katzenellenbogen

Index: Amos,R.A.; Katzenellenbogen,J.A. Journal of Organic Chemistry, 1978 , vol. 43, # 4 p. 555 - 560

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Citation Number: 35

Abstract

A copper enolate species derived by treatment of the lithium enolate of ethyl acetate with cuprous iodide has been found to react with propargyl bromide cleanly in an sN2'manner to give ethyl 3, 4-pentadienoate, a p-allenic ester. Under the same conditions, the lithium enolate gives only ethyl 4-pentynoate, the corresponding P-acetylenic ester, resu. lting from direct sN2 displacement. The reaction of propargylic methanesulfonates having an alkyl ...