Substituent effects on the transannular ring closure of 2,4-cyclooctadienones to 5,5-fused ring systems: an AM1 study


Zora M., Ozkan K.

JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, vol.583, pp.233-239, 2002 (SCI-Expanded) identifier identifier

Abstract

Substituent effects on the transannular ring closure of 2,4-cyclooctadienones to 5,5-fused ring systems were theoretically investigated by using AM1 method at the restricted HF level. As anticipated by elementary considerations, it was found that electron-donating substituents at positions 2 and 4 of cyclooctadienone lower the activation barrier, and make the transannular cyclization feasible. Substituents elsewhere on the ring including position 3 do not have a significant effect on the rearrrangement, their influence being mainly steric. (C) 2002 Elsevier Science B.V. All rights reserved.