Synthesis of 1, 5-dienes via [2+ 2] photocycloadditions between 2, 5-dihydrothiophene 1, 1-dioxides (sulfolenes) and. alpha.,. beta.-unsaturated cyclic ketones and …

JR Williams, C Lin, DF Chodosh

Index: Williams, John R.; Lin, Charles; Chodosh, Daniel F. Journal of Organic Chemistry, 1985 , vol. 50, # 26 p. 5815 - 5822

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Citation Number: 17

Abstract

Photocycloaddition between 2, 5-dihydrothiophene 1, l-dioxide (la) and 2-cyclohexenones 2a, b afforded cis-anti-cis and cis-trans photoadducts 3a, b and 4a in low yield. Photocycloaddition between sulfolene la and 2-cyclopentenones 8a, b yielded cis-anti-cis photoadducts 9a, b. The a-methyl derivative 9b underwent a-cleavage to yield the unsaturated aldehyde 10. Flash vacuum pyrolysis of photoadduct 3b yielded the trans-and ...