Srimontree Watchara, Masusai Chonticha, Soorukram Darunee, Kuhakarn Chutima, Reutrakul Vichai, Pohmakotr Manat
Center of Excellence for Innovation in Chemistry (PERCH-CIC) and Department of Chemistry, Faculty of Science, Mahidol University , Rama VI Road, Bangkok 10400, Thailand.
Faculty of Applied Science and Engineering, Khon Kaen University , Nong Khai Campus, Nong Khai 43000, Thailand.
J Org Chem. 2015 Nov 6;80(21):10512-20. doi: 10.1021/acs.joc.5b01562. Epub 2015 Oct 9.
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.
