title: Intramolecular Conjugate Ene Reaction of γ-Difluoromethyl- and γ-Trifluoromethyl-α,β-Unsaturated γ-Butyrolactones.
abstract: 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.
authors.affiliation: Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Department of Chemistry, Faculty of Science, Mahidol University , Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Watchara
authors.initials: W
authors.lastname: Srimontree
authors.affiliation: Faculty of Applied Science and Engineering, Khon Kaen University , Nong Khai Campus, Nong Khai 43000, Thailand.
authors.forename: Chonticha
authors.initials: C
authors.lastname: Masusai
authors.affiliation: Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Department of Chemistry, Faculty of Science, Mahidol University , Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Darunee
authors.initials: D
authors.lastname: Soorukram
authors.affiliation: Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Department of Chemistry, Faculty of Science, Mahidol University , Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Chutima
authors.initials: C
authors.lastname: Kuhakarn
authors.affiliation: Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Department of Chemistry, Faculty of Science, Mahidol University , Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Vichai
authors.initials: V
authors.lastname: Reutrakul
authors.affiliation: Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Department of Chemistry, Faculty of Science, Mahidol University , Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Manat
authors.initials: M
authors.lastname: Pohmakotr