Photochemical reactions. 145th Communication. Carbonyl vs. epoxyketone photochemistry: Photolysis of 1,2;3,4-diepoxy-2,6,6-trimethyl-1-cyclohexyl methyl ketone |
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Authors: | Rox Phaff Norbert Bischofberger Peter Mathies Walter Petter Bruno Frei Oskar Jeger |
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Abstract: | The synthesis and photolysis of the title compound 3 is described. Irradiation (λ > 280 nm, MeCN) of the di-epoxyketone 3 leads predominantly to γ–H abstraction. Cyclization furnishes the cyclobutanols 22 – 24 , while cleavage gives compound 25 , presumably via the allene-oxide intermediate 36 . Further, products 27 and 28 are formed by Norrish fragmentation and by initial cleavage of the C(α)? O bond of the oxirane, respectively. The structures of the products 22 – 25 , 27 , and 28 were assigned on the basis of the spectral data of the photolysis products of the 13C-labelled diepoxyketone[6,6-dimethyl-13C2]- 3 and by X-ray analysis of the compounds 24 and 35 , the latter being the p-nitrobenzoate of 22 . |
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