Shi Bin, Xiao Meng, Zhao Jin-Pu, Zhang Zhihan, Xiao Wen-Jing, Lu Liang-Qiu
Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, P. R. China.
Wuhan Institute of Photochemistry and Technology, Wuhan, Hubei 430082, P. R. China.
J Am Chem Soc. 2024 Oct 2;146(39):26622-26629. doi: 10.1021/jacs.4c10328. Epub 2024 Sep 18.
A Pd-catalyzed asymmetric higher-order dipolar cycloaddition between allenyl carbonates and azadienes is achieved by exploiting novel alkylidene-π-allyl-Pd dipoles. This research provides a modular platform for the synthesis of challenging chiral endocyclic allenes bearing a medium-sized heterocyclic motif and a centrally chiral stereocenter in good yields with high enantio- and diastereoselectivities (29 examples, up to 97% yield, 97:3 er and >19:1 dr). Experimental and computational studies elucidate the possible reaction mechanism and the observed stereochemical results. Based on the mechanistic understanding, a new π-propargyl-Pd dipole was designed to further extend the success of the higher order dipolar cycloaddition strategy to the synthesis of 10-membered endocyclic alkynes from propargyl carbonates and azadienes (13 examples, up to 98% yield and 94.5:5.5 er).
通过利用新型亚烷基-π-烯丙基钯偶极子，实现了碳酸亚丙二烯酯与氮杂二烯之间的钯催化不对称高阶偶极环加成反应。本研究提供了一个模块化平台，用于合成具有挑战性的手性内烯丙基化合物，该化合物带有中等大小的杂环基序和中心手性立体中心，产率高，对映选择性和非对映选择性高（29个实例，产率高达97%，对映体比例为97:3，非对映体比例>19:1）。实验和计算研究阐明了可能的反应机理和观察到的立体化学结果。基于对反应机理的理解，设计了一种新的π-炔丙基钯偶极子，以进一步将高阶偶极环加成策略的成功扩展到由碳酸炔丙酯和氮杂二烯合成10元内炔（13个实例，产率高达98%，对映体比例为94.5:5.5）。
