Model Calculation on the Stereoselectivity of the Triplet Photoreaction of 1,2-Dimethyltrimethylene



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The mechanism of stereodifferentiation was elucidated for the triplet ring-closure reaction of 1,2-dimethyltrimethylene (shown schematically on the right). The combined analysis of potential energy surfaces and spin-orbit coupling surfaces indicated that stereodifferentiation reflects the energetic behavior of the triplet state. This could well be a general feature of triplet photoreactions. ISC = inter-system crossing.