Interproton coupling over dual vicinal and homoallylic paths in 4-membered rings

✍ Scribed by Michael Barfield; Augustine A. Abia

• Book ID: 102530313
• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 296 KB
• Volume: 14
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270140515

✦ Synopsis

Abstract

A study is presented of cis and trans HH coupling over dual vicinal (HCCH) and homoallylic/interbenzylic/interbenzylic (HCCCCH) paths in the series of molecules cyclobutene and benzocyclobutanes, and a series of dihydrocyclobutacenaphthylenes. Both the experimental and calculated molecular orbital results for these molecules increase in magnitude as the π‐bond order of the homoallylic (interbenzylic) path decreases. These trends appear to be consistent only with homoallylic (interbenzylic) coupling contributions of negative sign. At least qualitatively, these trends can be rationalized in terms of the increase in positive contributions associated with the π→π* transitions as the energy denominators decrease in the series.