Synthesis, characterization and X-ray crystallography study of stable ylide of di-tert-butyl-2-(2-indolinon-1-yl)-3-(trimethoxyphosphorane ylidene) butanedioate

Abstract

Stable ylide of di-tert-butyl-2-(2-indolinon-1-yl)-3-(trimethoxyphosphorane ylidene) butanedioate was synthesized by means of catalyst-free reaction of trimethyl phosphite, di-tert-butylacetylene dicarboxylate and 2-indolinone in n-hexane/diethyl ether at ambient temperature. Obtained product was characterized by 1H, 13C, 31P NMR, FT-IR and mass spectroscopy. The crystal structure of the stable ylide was determined by X-ray crystallography. The title compound crystallized in monoclinic, space group P21/c and cell parameters a=15.8079(7) Å, b= 18.7521(13) Å, c =17.4987(10) Å, β= 95.504(6)° and Z=8. The X-ray study showed that adjacent carbonyl group (C291=O291, C191=O191) in the ylide moiety of compound had a resonance with bond of C=P. These results show clearly that environment of C(19, 29) is planar.

Keywords

• phosphorus stable ylide
• trimethyl phosphite
• di-tert-butylacetylene dicarboxylate
• x-ray crystallography