Affiliations: [a] College of Biological Science and Technology, University of Jinan, Jinan, Shandong, People’s Republic of China
| [b] Department of Neurology, The First Affiliated Hospital of Shandong First Medical University, Jinan, China
Correspondence:
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Corresponding authors. Jinsong Gu and Xiaojun Tan, College of Biological Science and Technology, University of Jinan, Jinan, Shandong, 250022, People’s Republic of China. Tel.: +86 0531 89736818; Fax: +86 0531 89736818; E-mail: gujs222@163.com (Jinsong Gu); E-mail: chem.2001@163.com (Xiaojun Tan).
Abstract: The mechanism of cycloaddition reaction between phosphenium cation and phosphindene with formaldehyde has been systematically investigated at the B3LYP/6-311++G(d,p) level of theory in order to better understand the reactivity for the valence isoelectronic of carbene. Phosphenium cation acts as an electrophilic reagent and accepts σ electrons of formaldehyde to form a complex in the first addition step. The greater the positive charge on phosphorus atom in phosphenium cation, the more stable the formed complex is. Introduction of substituents will decrease positive charge on phosphorus atom in phosphenium cation. The order of positive charge on phosphorus atom is HP+–F > HP+–OH > HP+–NH2, which is consistent with their Lewis acidities. The complex transforms to a three-membered ring product via a transition state in the second cyclization step. The product is less stable than the complex due to its tension of small ring.
