Zhang Qun-Liang, Xiong Qin, Li Miao-Miao, Xiong Wei, Shi Bin, Lan Yu, Lu Liang-Qiu, Xiao Wen-Jing
CCNU-uOttawa Joint Research Centre, Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, 430079, China.
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, China.
Angew Chem Int Ed Engl. 2020 Aug 10;59(33):14096-14100. doi: 10.1002/anie.202005313. Epub 2020 Jun 4.
Higher-order cycloadditions, particularly [8+2] cycloadditions, are a straightforward and efficient strategy for constructing significant medium-sized architectures. Typically, configuration-restrained conjugated systems are utilized as 8π-components for higher-order concerted cycloadditions. However, for this reason, 10-membered monocyclic skeletons have never been constructed via catalytic asymmetric [8+2] cycloaddition with high peri- and stereoselectivity. Here, we accomplished an enantioselective [8+2] dipolar cycloaddition via the merger of visible-light activation and asymmetric palladium catalysis. This protocol provides a new route to 10-membered monocyclic architectures bearing chiral quaternary stereocenters with high chemo-, peri-, and enantioselectivity. The success of this strategy relied on the facile in situ generation of Pd-containing 1,8-dipoles and their enantioselective trapping by ketene dipolarophiles, which were formed in situ via a photo-Wolff rearrangement.
高阶环加成反应,尤其是[8+2]环加成反应,是构建重要的中等大小结构的直接且高效的策略。通常,构型受限的共轭体系被用作高阶协同环加成反应的8π组分。然而,由于这个原因,从未通过具有高邻位和立体选择性的催化不对称[8+2]环加成反应构建出10元单环骨架。在此,我们通过可见光活化和不对称钯催化的结合实现了对映选择性[8+2]偶极环加成反应。该方法为带有手性季立体中心的10元单环结构提供了一条具有高化学、邻位和对映选择性的新途径。该策略的成功依赖于含钯1,8-偶极子的原位 facile 生成及其被烯酮亲偶极体的对映选择性捕获,烯酮亲偶极体是通过光沃尔夫重排原位形成的。