ABSTRACT
A number of reviews have been published concerning the synthetic utility of photochemical 2þ2 cycloadditions [1]. We have previously summarized the observed regio-and stereocontrol of photocycloaddition between alkenes and excited p systems [2]. Control of solution photochemistry has been demonstrated with use of templates, tethering of reagents, and substituent stabilization to affect the regioselectivity and/or stereoselectivity. The types of photoreactions that have been investigated using these techniques are numerous.
