ChemInform Abstract: MECHANISMUS DER AUSTAUSCHREAKTIONEN IN AMINOPHOSPHINEN, ALKOHOLYSE DER P(III)‐N‐BINDUNG, ZWISCHENPRODUKTE UND SEKUNDAERE REAKTIONEN

Abstract

Die Reaktion des Methoxyderivates (II) mit Methanol erfolgt in neutraler Lösung reversibel unter Ringöffnung und Weiterreaktion zu (III) und (IV).

Amides of Trivalent Phosphorus Acids as Phosphorylating Reagents for Proton-Donating Nucleophiles

“…The study of the rates of alcoholysis of ATPA showed that many reactions of this type are catalytic. This was found for the first time when the rates of phosphorylation of the simplest alcohols by phosph(III)amides thoroughly freed from possible impurities were compared with those by phosph(III)amides obtained by conventional methods and, hence, contaminated by some amine hydrochlorides (AHC). − Later, the discovered catalytic effect has been confirmed by many other researchers. ,,,− …”

“…Even in the first study dealing with the alcoholysis and phenolysis of simple ATPA, an “addition−elimination” mechanism was proposed for this reaction (Scheme ). Later, the possibility of the formation of hydrophosphoranes has been confirmed experimentally in studies dealing with some cyclic systems. − Simultaneously, a mechanism based on the formation of a four-membered transition state has been proposed for the alcoholysis of ATPA, but this has not been confirmed experimentally.

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“…It should be noted that in the early stage of the investigation of alcoholysis of phosphamides, several useful observations concerning the effects of the medium ,− and temperature on the reaction route have been made. In addition, it was found that phosphorylation slows down as amine resulting from the substitution is accumulated in the reaction mixture; apparently, this is due to complexation of the amine with the alcohol, which retards the main reaction. ,,,, …”

“…Nevertheless, it can be stated that some qualitative regularities have been elucidated to date. Thus, branched alcohols are normally less susceptible to phosphorylation than linear ones and secondary alcohols are inferior to primary ones. ,, High reactivity of ATPA toward phosphorylation of acidic alcohols 66 and especially phenols 10,14,15,17,66 has been reported. A distinctive feature of the latter compounds is that their reactivity depends appreciably on the solvent used. ,, It should be noted that intramolecular hydrogen bonds hamper phosphorylation of functionalized phenols…”

“…Attention is attracted by the high reactivity of mono- and diphenylamides, which has also been noted for other cases . Phosphopyrrolides, which possess an enhanced stability against alcoholysis, are unpromising reagents. ,,, Apparently, this is due to the exceptional inertness of the lone electron pair in pyrrole derivatives with regard to the formation of a hydrogen bond. Conversely, vinylamides of trivalent phosphorus acids (TPA) possess high phosphorylating capacity .…”