Ethynylogization of a coarctate fragmentation
Coarctate reactions form a separate class of elementary closed-shell processes in addition to polar and pericyclic reactions. Hence, they also follow a different homology principle. Whereas vinylogous polar and pericyclic reactions differ in the length of the reacting system by a double bond, coarctate reactions can be homologized (ethynylogized) by extending a known system by a triple bond. The prediction, which is based on theoretical considerations, is confirmed experimentally by the fragmentation of cyclopropylethynyl nitrene to cyano acetylene and ethylene, a reaction that is "ethynyloguous" to the known fragmentation of cyclopropyl nitrene to ethylene and HCN.
Herges
R
Institut fur Organische Chemie, Technische Universitat, Braunschweig, Germany. r.herges@tu-bs.de
Geuenich
D
Bucher
G
Tonshoff
C