Intramolecular Conjugate Ene Reaction of γ-Difluoromethyl- and γ-Trifluoromethyl-α,β-Unsaturated γ-Butyrolactones

Watchara SrimontreeChonticha MasusaiDarunee SoorukramChutima KuhakarnVichai ReutrakulManat PohmakotrMahidol UniversityKhon Kaen University2018-11-232018-11-232015-11-06Journal of Organic Chemistry. Vol.80, No.21 (2015), 10512-1052015206904002232632-s2.0-84946763259https://repository.li.mahidol.ac.th/handle/20.500.14594/35730© 2015 American Chemical Society. A general synthetic strategy to cis-fused bicyclic γ-butyrolactones via the retro-Diels-Alder reaction/intramolecular conjugate ene cascade (RDA/ICE) reaction under the flash-vacuum pyrolysis of maleic anhydride adducts is developed. The reaction gave high yields of products with high stereoselectivity. The existence of the difluoromethyl or trifluoromethyl group at the γ-position of the in situ-generated homoalkenyl- or homoalkynyl-α,β-unsaturated γ-butyrolactones was found to accelerate the rate of the intramolecular conjugate ene reaction leading to γ-difluoromethylated and γ-trifluoromethylated cis-fused bicyclic γ-butyrolactones.Mahidol UniversityChemistryIntramolecular Conjugate Ene Reaction of γ-Difluoromethyl- and γ-Trifluoromethyl-α,β-Unsaturated γ-ButyrolactonesArticleSCOPUS10.1021/acs.joc.5b01562