David G. Anderson, C. DePuy, J. Filley
Oct 1, 1984
Citations
0
Influential Citations
8
Citations
Journal
Journal of the American Chemical Society
Abstract
Abstract : The reactions of trimethyl phosphite were investigated with a series of nucleophiles. Products, branching ratios, and reaction rate constants are reported. Reactions generally proceed through an ion-dipole complex (Z-. (CH3O) 3P), to a phosphoranide anion intermediate, (CH3O)3PZ-), to displacement of methoxide to form a new ion-dipole complex (CH3O-(CH3O)2PZ). If an additional acidic hydrogen is available on the nucleophile, the major products result from proton abstraction by methoxide: (CH3O-.(CH30)2PYH) yield (CH30)2PY-+CH3OH. While the displacement of methoxide from phosphorus is sufficiently endothermic, a competing attack at carbon by the original nucleophile occurs: (HY-.(CH3O)3P) yields CH3YH+ (CH3O)2Po-. Nucleophiles without an additional acidic hydrogen react similarly, but the final reaction products result from 1) SN2 reaction of methoxide, 2) SN2 reaction of the original nucleophile, and 3) stabilization of the phosphoranide intermediate, and 4) expulsion of methoxide from the ion- dipole complex. Reaction mechanisms are discussed in terms of the nature of the nucleophiles, the observed products, and the thermodynamics of the displacement reaction. Originator-supplied keywords include: Flowing afterglow; Trimethyl phosphite; Reaction mechanisms; Phosphorous; and Nucleophilic displacement.