Malouf David M, Richardson Abigail D, L'Heureux Scott J, McDonough Elizabeth A, Henry Ava M, Sheng Jerry Y, Medhurst Erica A, Canales Angel E, Fleischer Cameron J, Cecil Ty B, Thurman Spencer E, McMullen Cameron C, Costanzo Philip J, Bercovici Daniel A
Department of Chemistry and Biochemistry, California Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93407, United States.
Org Lett. 2022 Apr 22;24(15):2793-2797. doi: 10.1021/acs.orglett.2c00630. Epub 2022 Apr 11.
Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with -mercaptoethanol to yield a mixture of four diastereomers. These four diastereomers fragment via a retro-[4 + 2] cycloaddition at differing rates. A simulated kinetics approach extrapolated the rate constants of the diastereomers from the observed rate data. YNDs display wide variability in rate of fragmentation, dependent on the stereoelectronics of the ylidene substituents. A substrate containing one carboxylic ester proved exceptionally stable to fragmentation.
由富烯与乙炔羧酸盐之间的[4 + 2]环加成反应制备的叶立德降冰片二烯（YNDs）与β-巯基乙醇反应，生成四种非对映异构体的混合物。这四种非对映异构体通过逆[4 + 2]环加成以不同速率裂解。一种模拟动力学方法从观察到的速率数据推断出非对映异构体的速率常数。YNDs的裂解速率变化很大，这取决于叶立德取代基的立体电子效应。含有一个羧酸酯的底物被证明对裂解异常稳定。
