Mass Spectrometry Used to Discriminate Between Cis‐Syn‐Cis and Cis‐Anti‐Cis Photoadducts

Abstract

Cis‐syn‐cis and cis‐anti‐cis regioisomers of tricyclo [6.2.0.02, 7] decan‐3‐ones or tricyclo [5.2.0.02, 6 nonan‐3‐ones, formed by (π2 + π2) photocycloaddition reactions between 1, 2‐bis (trimethylsiloxy) cyclobutene and 2‐cyclohexenones or 2‐cyclopentenones, respectively, are unequivocally identified by analysis of the isobutane chemical ionisation mass spectra.