where the central atom Z is commonly carbon. The reverse reaction is called α-addition.
Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1088 (https://doi.org/10.1351/pac199466051077)
General term applied to a reaction by which a group attached to the alpha carbon of an excited chromophore is expelled either as an odd electron species or as an ionic species.
Note: This reaction should be distinguished from an @A00004@.
Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 302 (https://doi.org/10.1351/pac200779030293)