)bicyclo[2.2.1]hept-5-en-2-alkoxides, which further undergo intramolecular cyclization to give the corresponding 2,3-dihydro-4-trifluoromethyl-5-X-furans. The corresponding alcohols (X = H, Cl) were isolated after quenching the reaction mixture at low temperature. The ring expansion process provides a simple synthetic procedure for the preparation of fluorinated norbornenes containing 2,3-dihydro-
用
LDA 或 RLi 试剂处理
降冰片烯氧杂
环丁烷 (4-halomethyl-4'-trifluoromethyl-3-oxatricyclo[4.2.1.0 2,5 ]non-7-enes) 会导致不寻常的扩环反应,导致相应的 2, 3-二氢-4-三
氟甲基-5-X-
呋喃(X = H、F、Cl、NC 4 H 9 )。这种转变在低温下迅速进行,并涉及相应开环产物的中间体形成,
锂 3-(1,1-dihalo-3,3,3-trifluoroprop-1-en-2-yl)bicyclo[2.2.1 ]hept-5-en-2-alkoxides,进一步进行分子内环化得到相应的 2,3-dihydro-4-trifluoromethyl-5-X-furans。在低温淬灭反应混合物后分离相应的醇(X = H,Cl)。扩环工艺为制备含 2、