手机知网 App
24小时专家级知识服务
打 开
手机知网|搜索

Organic Base Catalyzed Michael-Michael Cascade Reaction of(E)-Ethyl 2-Cyanohex-2-Enoate and Trifluoromethyl α,β-Unsaturated Ketones:A Highly Efficient Approach to Trifluoromethyl Dihydropyran

Fan Zhang;Jin-Tao Liu~* Key Laboratory of Organofluorine Chemistry;Shanghai Institute of Organic Chemistry;Chinese Academy of Sciences;345 Lingling Road;Shanghai 200032;China

  (E)-Ethyl-2-cynanohex-2-enoate reacted with trifluoromethylα,β-unsaturated ketones readily in the presence of 0.2 equivalent organic base,such as 1,4- diazabicyclo[2.2.2]octane(DABCO),N,N-4-dimethylaminopyridine(DMAP),and triethylamine,to give the corresponding trifluoromethyl substituted dihydropyrans in good yields.Only two diastereoisomers were obtained in a ratio of about 4:1.The relative configuration of the major diastereoisomer was determined by X-ray crystallographic analysis.……