Synthesis of Alkyl 2-(2-Oxo-1,2-dihydronaphtho [2,1-b]thiophen-1-yl)-2-(1,1,1-triphenyl-λ ⁵-phosphanylidene)acetates from Triphenylphosphine, Acetylenic Esters, and 2-Naphthalenethiol

Abstract

A one-pot synthesis of alkyl 2-(2-oxo-1,2-dihydronaphtho[2,1-b]thiophen-1-yl)-2-(1,1,1-triphenyl-λ⁵ -phosphanylidene)acetates in fairly high yields by the reaction of 2-naphthalenethiol, dialkyl acetylenedicarboxylates and triphenylphosphine is reported. The formulas of these compounds were confirmed by IR, ¹ H,³¹P, and ¹³C NMR spectroscopy. The NMR spectra indicated that solutions of the phosphorus ylides (CDCl₃ as solvent) contain two rotamers (E and Z). The relative percentages of rotamers in CDCl₃ for each phosphorus ylide were determined from the ³¹P NMR spectra.

Keywords:

• 2-Naphthalenethiol
• acetylenic esters
• Michael addition
• phosphorus ylide
• vinyltriphenylphosphonium salt

Acknowledgments

This work was supported by the Islamic Azad University-Abhar Branch.