EINE EINFACHE SYNTHESE FÜR ISOMERENREINE 1-CHLOR-1-OXO-PHOSPHOL-3-ENE

Abstract

Abstract Although the synthesis of 1-Chloro-1-oxo-phospholenes by (1 + 4)-cycloaddition of various trivalent Phosphorus compounds with at least one Phosphorus-Chlorine bond to 1,3-dienes has been investigated by different authors before, the influence of the reaction parameters, especially the molar ratios of the educts, has not been recognized in its importance toward the ratio of 2-and 3-Isomeres and the yield of the resulting 1-Chlor-1-oxo-phospholenes. From all described varieties, the reaction between Phosphorus-(III)chloride, Ethylenoxide and Buta-1,3-dien has proved to be the method of choice for a technical scale synthesis of 1-Chloro-1-oxo-phosphol-3-en. This paper reports the surprising effect of using nonstoichiometric amounts of Ethylenoxide, which leads to isomeric pure 1-Chloro-1-oxo-phosphol-3-en or to mainly 1-Chloro-1-oxo-phosphol-2-en when used in slight excess or deficit, respectively, thus offering a simple and convenient method for preparing definitive mixtures of both isomers in exce...