IIIT Hyderabad Publications |
|||||||||
|
Quantum Mechanical Studies on the Transannular Diels-Alder Reactions, and Related Pericyclic Reactions of 14-Membered Macrocyclic TrienesAuthors: V Prathyusha,U Deva Priyakumar Conference: Of Molecules and Materials (A Survey of Recent Concepts) (OMAM 2009 2009) Date: 2009-12-28 Report no: IIIT/TR/2009/258 AbstractTransannular Diels-Alder reaction (TADA) combines traditional pericyclic and intramolecular reactions, and has been shown to be one of the most efficient chemical transformations for synthesizing complicated natural products. TADA reactions occur in (x+y+2)-membered triene macrocycles, which contain both the diene and the dienophile, to form A.B.C[x.6.y] type tricyclic compounds. In addition, these macrocycles were shown to interconvert among its isomers via [1,5]-sigmatropic hydrogen shifts. The stereochemical outcome of the TADA reactions depends on the energetics of various possible transition states. Initially, a validation study was undertaken to assess the performance of various ab initio (HF, MPx, and CC) and hybrid density functional B3LYP methods using a variety of basis sets. Comparison of the reaction barriers, and reaction energies from various methods indicate that B3LYP/6-31G* level is appropriate enough for accurately modeling this class of reactions. All possible reaction pathways involving the TADA and 1,5-sigmatropic reactions of six different 14-membered triene molecules were studied using B3LYP/cc-pVTZ were calculated. Based on the reaction energy barriers and conformational properties of the reactants, the reactivities of these molecules will be discussed. Full paper: pdf Centre for Computational Natural Sciences and Bioinformatics |
||||||||
Copyright © 2009 - IIIT Hyderabad. All Rights Reserved. |