O'Connor Matthew J, Liu Huaqing, Lee Daesung, Zhou Tao, Xia Yuanzhi
Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago 60607, IL, USA.
Abbvie Inc., 1 North Waukegan Road, North Chicago 60064, IL, USA.
Molecules. 2015 Dec 2;20(12):21433-41. doi: 10.3390/molecules201219783.
The intramolecular [3+2] cycloaddition (32CA) of alkene-tethered α-silyloxydiazoalkanes provides variable stereoselectivity in generating bicyclic pyrazolines where the silyloxy group is either syn or anti to the newly formed pyrazoline ring. To elucidate the origin of the stereoselectivity, density functional theory (DFT) calculations were carried out for the energy of each transition state structure (TSs) and product. Steric effects were identified as the major determining factors in the diastereoselectivity of the 32CA reaction with regards to substrate structure (cyclic or acyclic α-silyloxydiazoalkanes).
烯烃连接的α-硅氧基重氮烷的分子内[3+2]环加成反应（32CA）在生成双环吡唑啉时具有可变的立体选择性，其中硅氧基与新形成的吡唑啉环处于顺式或反式。为了阐明立体选择性的起源，对每个过渡态结构（TSs）和产物的能量进行了密度泛函理论（DFT）计算。就底物结构（环状或非环状α-硅氧基重氮烷）而言，空间效应被确定为32CA反应非对映选择性的主要决定因素。
