Surpassing torquoelectronic effects in conrotatory ring closures: Origins of stereocontrol in intramolecular ketenimine-imine [2+2] cycloadditions

Citation
M. Alajarin et al., Surpassing torquoelectronic effects in conrotatory ring closures: Origins of stereocontrol in intramolecular ketenimine-imine [2+2] cycloadditions, CHEM-EUR J, 5(3), 1999, pp. 1106-1117
Citations number
66
Categorie Soggetti
Chemistry
Journal title
CHEMISTRY-A EUROPEAN JOURNAL
ISSN journal
09476539 → ACNP
Volume
5
Issue
3
Year of publication
1999
Pages
1106 - 1117
Database
ISI
SICI code
0947-6539(199903)5:3<1106:STEICR>2.0.ZU;2-T
Abstract
Intramolecular ketenimine-imine [2+2] cycloadditions leading to 1,2-dihydro azeto[2,1-b]quinazolines occur in a notably stereocontrolled manner along t he newly formed C-C single bond when prochiral ketenimine and imine fragmen ts are combined. Computational studies support stepwise mechanisms for thes e reactions. In sharp contrast with other well-known [2+2] cycloadditions, the first step of the reaction determines its stereochemical outcome, there by surpassing the low stereocontrol induced by torquoelectronic effects.