Stereoselectivity Control by Torsional
Steering in an Intramolecular
Diels-Alder Reaction of Vinyl
Oxocarbenium Ions
Robert G. Iafe andK. N. Houk*
Department of Chemistry and Biochemistry, University of California,
Los Angeles, California 90095-1569
houk@chem.ucla.edu
Received May 3, 2006
Abstract:
Density functional theory (B3LYP/6-31+G*) has revealed the origin of stereoselectivity in intramolecular Diels-Alder reactions of vinyl
oxocarbenium ions. The cycloaddition has endo preference and occurs with remote stereocontrol syn to the substituent at the stereogenic
center. Torsional steering, the preference for the staggered conformation about forming -bonds, dictates the preferred transition structure.
-bonds, dictates the preferred transition structure.
