Thermal Addition Reaction of Aroylketene with 1-Aryl-1-trimethylsilyloxyethylenes : Aromatic Substituent Effects of Aroylketene and Aryltrimethylsilyloxyethylene on Their Reactivity

Abstract

The thermal addition reaction of various aroylketenes (C) generated by the thermolysis of 5-aryldioxofurans (A) to 1-aryl-1-trimethylsilyloxyethylenes gave 1, 5-diarylpentane-1, 3, 5-triones (D) and 2, 6-diaryl-4H-pyran-4-ones (E). The introduction of electron withdrawing substituents in the aroylketene and of electron donating substituents facilitated the addition reaction. The observed substituent effects and the reaction mechanism are interpreted in terms of molecular orbital analyses.