Jiang Xuefeng, Ma Xiaojing, Zheng Zilong, Ma Shengming
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai, China.
Chemistry. 2008;14(28):8572-8. doi: 10.1002/chem.200800793.
Efficient room-temperature syntheses of cyclopentenes and 4,5-dihydrofurans with different substitution patterns were performed starting from the same materials (i.e., 2-(2',3'-allenyl)acetylacetates). Depending on the choice of metal catalyst, the Au-catalyzed reaction afforded C-attack-5-endo cyclization products 2, whereas the Pd-catalyzed one led to the formation of O-attack-5-exo cyclization products 3. The selectivity may be explained by the steric and electronic effects of the substrates and catalysts.
从相同的原料（即2-(2',3'-联烯基)乙酰乙酸酯）出发，高效地在室温下合成了具有不同取代模式的环戊烯和4,5-二氢呋喃。根据金属催化剂的选择，金催化的反应得到C-进攻-5-内型环化产物2，而钯催化的反应则导致形成O-进攻-5-外型环化产物3。这种选择性可以通过底物和催化剂的空间和电子效应来解释。
