Study of the addition of monoalkylphosphonic acids onto trialkyl-substituted epoxides.
The addition of 2-chloroethylphosphonic acid (or ethephon), a well-known stimulating molecule for the production of latex by Hevea brasiliensis, onto 2,3-epoxy-2-methylbutane was investigated to enhance the understandings on the addition mechanisms of reagents of alkylphosphonic acid type onto trialkyl-substituted epoxides. It was demonstrated that the addition occurs according to a three-step mechanism including a rapid nucleophilic attack of the phosphorated anion on the most alkyl-substituted carbon of the oxirane, followed by formation of a dioxaphospholane structure with release of water, and finally a hydrolytic cleavage of the dioxaphospholane cycle to generate the regioisomer 1:1 adduct where the phosphorated group is on the less alkyl-substituted carbon of the initial oxirane.
Derouet
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L.C.O.M. Chimie des Polymères (Unité Mixte de Recherche du CNRS LCO2M No. 6011), Université du Maine, Avenue Olivier Messiaen, F-72085 Le Mans Cedex 9, France. Daniel.Derouet@univ-lemans.fr
Cauret
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Brosse
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