Zhang Hao, Zhu Le, Wang Shaozhong, Yao Zhu-Jun
State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University , 22 Hankou Road, Nanjing, Jiangsu 210093, China.
J Org Chem. 2014 Aug 1;79(15):7063-74. doi: 10.1021/jo501196n. Epub 2014 Jul 15.
Asymmetric annulation of 3-alkynylacrylaldehydes with 2-hydroxystyrenes has been studied and achieved by synergetic catalysis from AgOAc and chiral phosphoric acid, providing the corresponding multiring products with decent total yields and moderate to excellent enantioselectivities (up to 95% ee). The developed mild multibond-formation cascade reaction involves in situ generation of pyrylium intermediate by Ag(I)-catalyzed alkyne/carbonyl cycloisomerization, counteranion-directed asymmetric oxa [4 + 2]-cycloaddition, and intramolecular nucleophilic substitution.
通过醋酸银和手性磷酸的协同催化，对3-炔基丙烯醛与2-羟基苯乙烯的不对称环化反应进行了研究并取得成功，得到了相应的多环产物，总收率可观，对映选择性中等至优异（高达95% ee）。所开发的温和多键形成级联反应涉及通过银（I）催化的炔烃/羰基环异构化原位生成吡喃鎓中间体、抗衡阴离子导向的不对称氧杂[4 + 2]环加成反应以及分子内亲核取代反应。
