Controllable Cyclization Reactions of 2-(2′,3′-Allenyl)acetylacetates Catalyzed by Gold and Palladium Affording Substituted Cyclopentene and 4,5-Dihydrofuran Derivatives with Distinct Selectivity
作者:Xuefeng Jiang、Xiaojing Ma、Zilong Zheng、Shengming Ma
DOI:10.1002/chem.200800793
日期:2008.9.26
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
从相同的材料(即2-(2',3'-烯基)乙酰乙酸酯)开始,高效地合成具有不同取代方式的环戊烯和4,5-二氢呋喃。根据金属催化剂的选择,Au催化的反应提供了C-attack-5-exo环化产物2,而Pd催化的反应导致了O-attack-5-exo环化产物3的形成。可以通过底物和催化剂的空间和电子效应来解释。