Synthesis of Alkyl 6-(2-Alkoxy-2-oxoethyl)dibenzo[d,f][1,3]dioxepine-6-carboxylates from Stabilized Phosphorus Ylides

Author: Ramazani, Ali

Source: Phosphorus, Sulfur, and Silicon and the Related Elements, Volume 184, Number 2, February 2009 , pp. 536-541(6)

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, by biphenyl-2,2' -diol leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction with a conjugate base to produce the corresponding stabilized phosphorus ylides. Magnesium oxide powder was found to catalyze the conversion of the stabilized phosphorus ylides to alkyl 6-(2-alkoxy-2-oxoethyl)dibenzo[d,f][1,3]dioxepine-6-carboxylates in solvent-free conditions under microwave (0.5 KW, 3 min) and thermal (90 °C, 60 min) conditions.

Keywords: Acetylenic esters; biphenyl-2,2'-diol; [1,3]dioxepine; magnesium oxide; Michael addition; microwave irradiation; vinyltriphenylphosphonium salt

Document Type: Research article

DOI: http://dx.doi.org/10.1080/10426500802208433

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

Publication date: 2009-02-01