Izquierdo Marta, Osuna Sílvia, Filippone Salvatore, Martín-Domenech Angel, Solà Miquel, Martín Nazario
Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, E-28040 Madrid, Spain.
J Org Chem. 2009 Feb 20;74(4):1480-7. doi: 10.1021/jo802152x.
The one-step reaction of 2,6-dihydroxyphenylmethyl ketone and sarcosine with [60]fullerene in refluxing chlorobenzene affords, in a totally regioselective process, the cis-1 bicyclic-fused organofullerene through a new intramolecular nucleophilic addition of one hydroxy group to the fullerene double bond. Experimental findings reveal the presence of a methyl group on C-2 of the pyrrolidine ring as an essential requirement for the cyclization process, whereas the existence of a H-bond between a second hydroxylic group and the nitrogen atom of the pyrrolidine ring seems to favor the approaching geometry without determining the reaction outcome. Theoretical calculations using the two-layered ONIOM approach and density functional theory support the experimental findings, predicting the strong impact that the presence of the methyl substituent on the C-2 of the pyrrolidine ring has on the molecular geometry and, hence, on the intramolecular cyclization process.
2,6 - 二羟基苯甲基酮与肌氨酸在回流的氯苯中与[60]富勒烯发生一步反应，通过一个新的分子内亲核加成反应，即将一个羟基加成到富勒烯双键上，以完全区域选择性的方式得到顺式 - 1双环稠合有机富勒烯。实验结果表明，吡咯烷环C - 2上甲基的存在是环化过程的必要条件，而第二个羟基与吡咯烷环氮原子之间氢键的存在似乎有利于接近的几何构型，但并不决定反应结果。使用双层ONIOM方法和密度泛函理论进行的理论计算支持了实验结果，预测了吡咯烷环C - 2上甲基取代基的存在对分子几何构型以及分子内环化过程的强烈影响。
