Reaction of Perfluoro (2-methyl-2-pentene) with 2-Mercaptoethanol

Abstract

In the presence of a variety of bases as a catalyst the reaction of perfluoro(2-methyl-2pentene) [1] with 2-mercaptoethanol [2] in acetonitrile was investigated to know the effect of their basicity both on the kind and yield of each product. Of particular interest is the fact that the products and yields are markedly affected not only by the basicity of catalyst but also the order of addition of starting materials.
In the presence of triethylamine, dropwi se addition of the [2] to a solvation of [1] in acetonitrile, gave a five-membered heterocyclic compound, 2-pentafluoroethy1-2[1 H-perfluoro(1-methyl-ethyl)]-1, 3-oxathiolane [4]as the sole product, in 92% yield.
On the contrary, the compound [4] and bis[perfluoro(1-ethy1-2-me thyl-l-propenyloxy)ethyl] disulfide [7] were obtained as the main products, when the order of addition was reversed.
On the other hand, the reaction of [1] with [2] using potassium fluoride or potassium carbonate as a basic catalyst is more complex and afforded the compound [4 ], a sevenmembered heterocyclic compound, 5, 7-difluoro-5-pentafluoroethy1-6-trifluoromethy1-2, 3dihydro-5 H-1, 4-oxathiepin [5], 2-[perfluoro(1-ethyl-2-methyl-1-propenylthio)]ethanol [3], and 1-[perfluoro (1-ethyl-2-methyl-l-propenyloxy)]-2-[perfluoro(1-ethyl-2-methyl-1-propenylthio)]ethane [6]. In the case of potassium fluoride or potassium carbonate being used, the kinds of products were not affected so much by the order of addition of reagents.
These results are summarized in Tables 1 and 2.