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
Palladium-Catalyzed Three-Component Tandem Cyclization Reaction of 2-(2,3-Allenyl)acylacetates, Organic Halides, and Amines: An Effective Protocol for the Synthesis of 4,5-Dihydro-1H-pyrrole Derivatives
作者:Jiajia Cheng、Xuefeng Jiang、Can Zhu、Shengming Ma
DOI:10.1002/adsc.201100002
日期:2011.7
A domino three‐component reaction of 2‐(2′,3′‐allenyl)acylacetates with aryl or alkenyl halides and aryl‐ or benzylamines afforded 4,5‐dihydro‐1H‐pyrrole derivatives highly chemo‐ and regioselectively in one pot through imine formation/imine‐enamine tautomerization under the catalysis of palladium(0) and toluenesulfonic acid monohydrate. A high diastereoselectivity was observed.
Electrophilic Cyclization of 2-(2′,3′-Allenyl)acetylacetates with Iodine Using Calcium Hydride as the Base
作者:Baoqiang Wan、Xuefeng Jiang、Guochen Jia、Shengming Ma
DOI:10.1002/ejoc.201200527
日期:2012.8
A facile and efficient protocol for the synthesis of 4,5-dihydrofuran derivatives via iodine-mediated cyclization of various 2-(2′,3′-allenyl)acetylacetates with CaH2 as the base has been developed. The yields range from moderate to good. The resulting products can be used for further elaboration by palladium-catalyzed coupling reactions.