Regio- and Stereoselective Addition of 1,2,3,6-Tetrahydrophthalimide to Electron-Poor Acetylenic Esters in the Presence of Triphenylphosphine

Authors: Mahyari, Amir Tofangchi¹; Shajari, Nahid²; Ahmadi, Ebrahim¹; Ramazani, Ali¹

Source: Phosphorus, Sulfur, and Silicon and the Related Elements, Volume 182, Number 7, July 2007 , pp. 1653-1659(7)

Publisher: Taylor and Francis Ltd

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Abstract:

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates (or alkyl acetylenecarboxylates), by 1,2,3,6-tetrahydrophthalimide leads to vinyltriphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce phosphorus ylides. Dipotassium hydrogen phosphate and silica gel were found to catalyze conversion of the phosphorus ylides to electron-poor N-vinyl imides in solvent-free conditions under thermal (80-90°C, 40-50 min) conditions. The structural analysis of the products indicated that the reaction is regio- and stereoselective.

Keywords: Acetylenic esters; dipotassium hydrogen phosphate; electron-poor N-vinyl imide; regioselective; stereoselective; silica gel; vinyltriphenylphosphonium salt

Document Type: Research article

DOI: http://dx.doi.org/10.1080/10426500701289831

Affiliations: 1: Chemistry Department, Zanjan University, Zanjan, Iran 2: Chemistry Department, Zanjan University, Zanjan, Iran,Chemistry Department, Islamic Azad University-Zanjan Branch, Zanjan, Iran

Publication date: 2007-07-01