Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Faculty of Chemistry, Northeast Normal University , Changchun 130024, P. R. China.
State Key Laboratory of Fine Chemicals, Dalian University of Technology , Dalian 116024, P. R. China.
J Org Chem. 2017 Nov 3;82(21):11348-11357. doi: 10.1021/acs.joc.7b01635.
DBU-catalyzed sequential intermolecular and intramolecular nucleophilic addition reactions between gem-difluoroolefins and o-hydroxy/mercapto benzaldehydes have been developed to provide a [4 + 2] annulation strategy for facile synthesis of gem-difluorinated isoflavanol derivatives. The competitive addition-elimination reaction of gem-difluoroolefins with nucleophiles was avoided under mild conditions, affording 2,2-difluorinated 4-isoflavanols or 2,2-difluoriated 4-thioisoflavanols in good to excellent yields.
DBU 催化的偕二氟烯烃与邻羟基/巯基苯甲醛之间的串联分子间和分子内亲核加成反应，为简便合成偕二氟异黄酮衍生物提供了一种[4+2]环加成策略。在温和条件下避免了偕二氟烯烃与亲核试剂的竞争性加成-消除反应，以良好至优异的收率得到了 2,2-二氟代 4-异黄酮醇或 2,2-二氟代 4-硫代异黄酮醇。
