Pudovik-type addition

Symmetrical triazines, although not formally unsaturated, in the presence of the dialkyl phosphites undergo ring opening and selfcatalysis for Pudovik-type addition.318-322 An example is shown in Equation 3.19. 

A variety of reaction conditions have been employed for Pudovik-type additions to imines, including the use of additional tertiary amines,323 324 sodium hydride,325 and sodium ethoxide,326/327 as well as monobasic trivalent phosphorus-containing acids.319/328-340... 

A unique example of a chiral calix[4]arene functionalized at the upper rim with an amino acid is the aminophosphonic acid derivative 8 (Fig. 2.2). Its synthesis using Pudovik-type addition was reported recently by the group of Kalchenko... 

A logical extension of the Abramov- and Pudovik-type reactions at carbonyl carbon is the conjugate addition of the phosphorus reagents at distant sites of conjugated carbonyl and related systems. A wide range of such Michael addition reactions, many of significant practical... 

The use of an anionic reagent for addition at carbonyl carbon rather than a fully esterified form of a trivalent phosphorus acid obviates a troublesome aspect of the Abramov reaction. Specifically no dealkylation step is required. Mechanistic investigations257 258 indicate that the reaction proceeds much as a simple "aldol"-type reaction in which the anionic phosphorus site adds directly to the carbonyl center. While the initial efforts concerned with the "Pudovik reaction"259 were directed toward the use of sodium salts of the simple dialkyl phosphites, as shown in Equation 3.17,260 266 with a, 5-unsaturated carbonyl systems (vide infra) competition between sites for addition can occur. Addition at the carbonyl carbon site is the kinetically favored route.267-270... 

Kinetic studies of the alcoholate-promoted Pudovik addition of dialkyl H-phosphonates to a-enones reveal that depending on the type of the substituents at the enone system, the following interactions take place [140,141] ... 

The Pudovik addition of diethyl H-phosphonate to nitrosubstituted aUcenes of the type Ph2C=CRN02 in DMSO or excess diethyl H-phosphonate yields the aziridine I (R = H, Me, Ph), formed presumably via the azirine II [150, 151],... 

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