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[摘要]：Irradiation of the title thioesters (Z)-1 in nitrogen-saturated 1,2-dichloroethane at wavelengths greater, than 280 nm was found to afford (Z)-4-(1-naphthylmethylene)-5(4H)-oxazolone derivatives (Z)-2, (E)-2, alkyl-substituted thiols 3, and (E)-1 without forming any thio-radical-derived products. An analysis of the substituent and solvent effects on the reactivity of 1 and the product distribution demonstrated that the heterolytic C(=O)-S bond cleavage products 2 and 3 are not derived from the long-lived acylium and thiolate ions but from the protonated oxazolone/thiolate ion pair. The latter intermediates were assumed to be formed by the sulfur-assisted nucleophilic addition of the N-acyl carbonyl oxygen to the thioester carbonyl carbon in the excited state, followed by the elimination of the thiolate ion from the resulting adducts. |
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