The<unk>  is a photochemical reaction of a molecular entity comprising two π-systems, separated by a saturated carbon atom (a 1,4-diene or an allyl-substituted aromatic analog), to form an ene- (or aryl-) substituted cyclopropane. The<unk>  formally amounts to a 1,2 shift of one ene group (in the<unk> ene) or the aryl group (in the allyl-aromatic analog) and ‘bond formation’ between the lateral carbons of the non-migrating moiety.
Di-pi-methane rearrangement
Fischer esterification
Carboxylation
Deprotonation
Hydrogen-deuterium exchange
Thermal depolymerization
Alkyne metathesis
Hydroxylation