Peer-Reviewed Journal Details
Mandatory Fields
Byrne, PA;Gilheany, DG
2016
June
Chemistry - A European Journal
The Mechanism of Phosphonium Ylide Alcoholysis and Hydrolysis: Concerted Addition of the O-H Bond Across the P=C Bond
Validated
Optional Fields
CATALYTIC WITTIG REACTION NUCLEAR-MAGNETIC-RESONANCE TERTIARY PHOSPHINE OXIDES ALKALINE-HYDROLYSIS THERMAL-DECOMPOSITION EQUILIBRIUM ACIDITIES HETEROARYLPHOSPHORUS COMPOUNDS NUCLEOPHILIC DISPLACEMENT ALKOXYPHOSPHONIUM HALIDES SUBSTITUTION REACTIONS
22
9140
9154
The previous work on the hydrolysis and alcoholysis reactions of phosphonium ylides is summarized and reviewed in the context of their currently accepted mechanisms. Several experimental facts relating to ylide hydrolysis and to salt and ylide alcoholysis are shown to conflict with those mechanisms. In particular, we demonstrate that the pK(a) values of water and alcohols are too high in organic media to bring about protonation of ylide. Therefore, we propose concerted addition of the water or alcohol O-H bond across the ylide P=C bond. In support of this, we provide NMR spectroscopic evidence for equilibrium between ylide and aclohol that does not require the involvement of phosphonium hydroxide. We report the first P-alkoxyphosphorane to be characterised by NMR spectroscopy that does not undergo exchange on an NMR timescale. Two-dimensional NMR spectroscopic techniques have been applied to the characterisation to P-alkoxyphosphoranes for the first time.
WEINHEIM
0947-6539
10.1002/chem.201600530
Grant Details