Zhao Zhenqi, Popov Stasik, Lee Woojin, Burch Jessica E, Delgadillo David A, Kim Lee Joon, Shahgholi Mona, Lebrón-Acosta Naiara, Houk K N, Nelson Hosea M
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States.
Org Lett. 2024 Feb 9;26(5):1000-1005. doi: 10.1021/acs.orglett.3c04014. Epub 2024 Jan 31.
Medium-sized rings (8-11-membered cycles) are often more challenging to synthesize than smaller rings (5-7-membered cycles) due to ring strain. Herein, we report a catalytic method for forming 8- and 9-membered rings that proceeds via the intramolecular Friedel-Crafts reactions of vinyl carbocation intermediates. These reactive species are generated catalytically through the ionization of vinyl toluenesulfonates by a Lewis acidic lithium cation-weakly coordinating anion salt.
由于环张力的原因，中等大小的环（8至11元环）通常比小环（5至7元环）更具合成挑战性。在此，我们报告一种形成8元和9元环的催化方法，该方法通过乙烯基碳正离子中间体的分子内傅克反应进行。这些活性物种是通过路易斯酸性锂阳离子-弱配位阴离子盐使乙烯基甲苯磺酸酯离子化而催化生成的。
