The Reaction of Ketenylidenetriphenylphosphorane (Ph₃P˭C˭C˭O) with Acidic H‒E (E˭O, N) Bonds

Abstract

The reactivity of ketenylidenetriphenylphosphorane (1) with the protic reagents 2,4,6-trimethylphenol (7), 2,6-di-tert-butyl-4-methylphenol (8), and diphenylamine (9) has been explored. Three novel carbonyl-stabilized ylides have been synthesized and characterized. Crystal structures were obtained for Ph₃PCHC(O)O(C₆H₂Me₃) (11), Ph₃PCHC(O)O(C₆H₂t-Bu₂Me) (12), and Ph₃PCHC(O)NPh₂ (13), respectively. These products were then methylated in an attempt to develop a new route to low-valent carbon compounds. Crystals of [Ph₃PCH(CH₃)C(O)O(C₆H₂Me₃)]I (14) were isolated and characterized but this route did not prove to be synthetically useful, at least toward the goal of preparing low-valent carbon-centered materials. Finally, 1 was also reacted with the bulky tin reagent, bis[bis(trimethylsilyl)amido]tin(II), in the presence of 2,4,6-trimethylphenol. A complex mixture of products was obtained, from which crystals of an unusual chelated tin compound (15) were isolated and characterized using X-ray crystallography.

GRAPHICAL ABSTRACT

Keywords:

• X-ray crystallography
• ketenylidenetriphenylphosphorane
• phenols
• diphenylamine
• 1,2-addition
• stabilized P-ylide

Acknowledgments

Funding was provided by the Natural Sciences and Engineering Council of Canada (NSERC) through the Discovery Grants Program to J.D.M. and J.A.C.C. J.A.C.C. acknowledges generous support from the Canada Research Chairs Program, the Canadian Foundation for Innovation, and the Nova Scotia Research and Innovation Trust Fund. The authors are also grateful to NMR-3 (Dalhousie University) for NMR data acquisition.