Fate of Diradicals in the Caldera: Stereochemistry of Thermal Stereomutation and Ring Enlargement in <i>cis</i>- and <i>trans</i>-1-Cyano-2(<i>E</i>)-propenylcyclopropanes
作者:William von E. Doering、Edward Albert Barsa
DOI:10.1021/ja0305961
日期:2004.10.1
ane [(-)-trans-1] and (+)-cis-1-cyano-2(E)-propenylcyclopropane [(+)-cis-1] to cyclopentenes definitively contraindicates the usefulness of Woodward-Hoffmann rules of orbital symmetry as a theoretical basis for predicting the stereochemistry of the products. From both diastereomers, the same (+)-trans-4-cyano-3-methylcyclopentene [(+)-trans-2] is the major product among the four diastereomeric products
这项研究 (-)-trans-1-cyano-2(E)-propenylcyclopropane [(-)-trans-1] 和 (+)-cis-1-cyano-2(E) 中的热诱导立体突变和环扩大)-丙烯基环丙烷 [(+)-cis-1] 到环戊烯明确禁止伍德沃德-霍夫曼轨道对称规则作为预测产物立体化学的理论基础的有用性。从两种非对映异构体中,相同的 (+)-trans-4-cyano-3-methylcyclopentene [(+)-trans-2] 是四种非对映异构体产品中的主要产品,“允许”并且形式上是单一内部旋转的结果来自 (-)-trans-1 的含氰基碳原子的“禁止”和来自 (+)-cis-1 的零内旋的结果。在旋转倾向、热力学偏好、