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Paper | Regular issue | Vol 27, No. 9, 1988, pp.2153-2166
Published online, 1st January, 1970
DOI: 10.3987/COM-88-4590
Thermal and Photochemical Oxetane Formation with α-Ketoesters

Jochen Mattay* and Karl Buchkremer

*Institut für Organische Chemie, Rheinisch-Westfälische, Technische Hochsch, Professor-Pirlet-Straße 1, D-52074 Aachen, Germany

Abstract

The thermal and photochemical [2+2]-cycloadditions of ethyl pyruvate, diethyl mesoxalate and biacetyl with 1,1-diethoxyethene, 2,2-diisopropyl-1,3-dioxole and 1,1-dimethoxy-2-methylpropene have been studied. 1,1-Diethouyethene forms oxetanes at room temperature with all carbonyl compounds as well as 1,1-dimethoxy-2-methylpropene and diethyl mesoxalate whereas the other electron-rich olefins generally react only in presence of Lewis-acids as catalysts.These observations indicate the energetic preference of the [1DS+1AS] geometry of the transition state according to Houk’s MO-treatment rather than the [2DS+1AS] geometry for symmetrical olefins. In general the photoreaction is complementary to the therrnal oxetane formation in both the reactivity and the regioselectivity. Only the electron poorest acceptor diethyl mesoxalate did not show any photochemical addition onto these olefins.