A theoretical study of the mechanism and selectivity of the intramolecular 1,3-dipolar cycloaddition reaction of the nitrone-alkene derived from 2-allylthiobenzaldehyde for the synthesis of tricyclic isoxazolidines

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• 作者：Fouad Chafaa^a ; Djamila Hellel^a ; Abdelmalek Khorief Nacereddine^a ; ^b ; ^{malek_khorief@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Abdelhafid Djerourou^a
• 关键词：Cycloaddition ; Selectivity ; Mechanism ; DFT calculations ; Intramolecular ; Isoxazolidines
• 刊名：Tetrahedron Letters
• 出版年：2016
• 出版时间：6 January 2016
• 年：2016
• 卷：57
• 期：1
• 页码：67-70
• 全文大小：627 K

文摘

A computational study of the mechanism as well as the regio- and stereoselectivities of the intramolecular 1,3-dipolar cycloaddition (IMDC) of nitrone–alkene 1, derived from 2-allylthiobenzaldehyde, has been carried out using DFT methods at the MPWB1K/6-31G(d,p) level of theory. The four possible pathways, fused and bridged regioisomeric modes, and the two stereoisomeric approaches endo and exo for the IMDC reaction are analyzed and discussed. Analysis of the potential energy surface showed that this IMDC reaction kinetically favors formation of the isoxazolidine generated from the fused-endo pathway. The obtained results corroborate very well with the published experimental data. Analysis of TS geometries and bond order indicate that these IMDC reactions proceeded through a one-step synchronous mechanism for the fused modes and is asynchronous for the bridged modes.