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Tertiary phosphines have been recognized as powerful organocatalysts for the Michael reaction, which is one of the most important atom-economical methods for carbon-carbon and carbon-heteroatom bond construction. In the presence of tertiary phosphines, a vast array of Michael acceptors and Michael donors can be coupled with each other under neutral and metal-free conditions to produce useful densely functionalized molecules. This review highlights the role of phosphine-catalyzed Michael reaction in cutting-edge areas, such as asymmetric synthesis, natural products synthesis, drug design, and polymer material science. As the central part of catalysis science, the kinetic and mechanistic issues are also discussed when possible. The review is organized by the type of the Michael acceptor and the Michael donor used in the reaction. [ABSTRACT FROM AUTHOR]

The previously proposed mechanism for phospha-Michael addition of tertiary phosphines to electron-deficient alkenes has been amended according to the secondary kinetic isotope effects provided by α-deuterated activated alkenes. The data obtained have shown that rate-determining protonation of intermediate phosphonium zwitterion proceeds not directly at its carbanionic center but first at a heteroatom of the attached electron-withdrawing group, with subsequent isomerization of the enolic/eniminic intermediate to stable keto-/cyanophosphonium product. [ABSTRACT FROM AUTHOR]

Kinetic data provide evidence that proton transfer to the carbanion centre of a phosphonium zwitterion is the rate-determining step in quarternization reactions of triphenylphosphine with electron-deficient alkenes in solution. This conclusion is based on the third-order , the reactivity of the alkenes, and solvent isotope effects in deuteroacetic acid. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The structures of intermediates and transition states in the reaction of tertiary phosphines with unsaturated carboxylic acids have been calculated at the B3LYP level of theory using the 6-31+G(d,p) basis set. Analysis of the results shows that [1,3]-intramolecular migration of carboxylic proton to carbanionic center of generated zwitterionic intermediate is strongly kinetically unfavorable, and external proton-donor source is essential to complete quaternization. A molecular cluster of the intermediate with one molecule of water has been modeled for intermolecular reaction pathway, but even in this case, the proton transfer remains to be the rate-determining step that is in a good agreement with previous kinetic investigations on this reaction. The data obtained for this reaction have much in common with recent studies on the mechanisms of the Morita-Baylis-Hillman reaction and phosphine-catalyzed [3+2] cycloaddition, which revealed paramount importance of proton-transfer steps. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The catalytic activity of hexamethyltriaminophosphine in the P(O)–H bond addition to electron-deficient alkenes was studied. Depending on the nature of the alkene, hexamethyltriaminophosphine produces better or lower yields of the reaction products compared to tri-n-butylphosphine. [ABSTRACT FROM AUTHOR]