Photoassisted Diversity-Oriented Synthesis: Intramolecular Cycloadditions of Photogenerated Azaxylylenes with Oxazole Pendants, and Subsequent Postphotochemical Multicomponent Modifications

Photogenerated
aza-o-xylylenes undergo intramolecular
cycloaddition reactions to tethered oxazoles, with primary photoproducts
featuring a reactive cyclic imine moiety suitable for multicomponent
postphotochemical transformations. For example, the reaction of these
imine photoproducts with bromoacetyl bromide leads to a key 1,4-dielectrophilic
synthon, offering access to diverse polyheterocyclic molecular architectures.
This reaction sequence is accompanied by rapid growth complexity in
a very few simple synthetic steps, and is in keeping with the philosophy
of diversity-oriented synthesis (DOS).