ABSTRACT
The geometrical photoisomerization of alkenes was reviewed also in the previous edition.
However, the photobehavior of cycloalkenes is not a simple extension of that of acyclic alkenes, particularly in the cases of small-and medium-sized cycloalkenes. Medium-sized (
E
)-cycloalkenes produced photochemically are highly constrained and rapidly react with alcohols in the presence, or even in the absence, of dilute acid. An account of the photoprotonation-driven cationic reactions, such as addition, isomerization, rearrangement, and fragmentation of cyclohexenes and cycloheptenes, in protic solvents has been published.
