On the origin of cis/trans stereoselectivity in intramolecular Diels-Alder reactions of substituted pentadienyl acrylates: A comprehensive density functional study

Paddon-Row, Michael N., Moran, Damian, Jones, Garth A. and Sherburn, Michael S. (2005) On the origin of cis/trans stereoselectivity in intramolecular Diels-Alder reactions of substituted pentadienyl acrylates: A comprehensive density functional study. The Journal of Organic Chemistry, 70 (26). pp. 10841-10853.

Full text not available from this repository. (Request a copy)

Abstract

A gas-phase B3LYP/6-31+G(d) study of substituent effects on the stereochemistry of both intramolecular Diels-Alder UMDA) reactions of 9-E- and 9-Z-substituted pentadienyl acrylates and intermolecular Diels-Alder (DA) reactions between butadiene and monosubstituted alkenes and 3-substituted acrylates is reported and involves the calculation of 230 transition structures. It was found that, although exo ("anti-Alder") addition of monosubstituted ethenes to butadiene is the norm, Alder endo selectivity is more widely predicted for 3-substituted methyl acrylate dienophiles, and this was explained in terms of secondary orbital interactions (SOIs). Whereas cis/trans selectivity for IMDA reactions involving 9-E-substituted pentadienyl acrylates generally follows the normal pattern found for the corresponding intermolecular DA reactions, the 9-Z-substituted stereoisomers generally displayed trans selectivity that was much stronger than can be attributed to effects of the isolated substituent. This is strikingly so with unsaturated electron-withdrawing substituents whose endo selectivities, displayed in intermolecular DA reactions, are reversed in the IMDA reactions of pentadienyl acrylates. The origin of this anomalous Z-effect is explained in terms of the twist-mode asynchronicity concept of Brown and Houk. These ideas are used to explain the stereochemical outcomes of IMDA reactions of other triene systems.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Depositing User: Rachel Smith
Date Deposited: 20 Apr 2011 15:14
Last Modified: 03 Jun 2020 23:40
URI: https://ueaeprints.uea.ac.uk/id/eprint/29765
DOI: 10.1021/jo051973q

Actions (login required)

View Item View Item