Ionic and radical fragmentations of alkoxyhalocarbenes - a perspective

摘要

Fragmentations of secondary or tertiary alkoxyhalocarbenes In polar solvents generate carbocations as components of ion pairs. A variety of carbocations can be produced including acyclic, alicyclic, benzyl, bridgehead, cyclopropyl, cyclopropylcarbinyl, and norbornyl examples. Laser flash photolysis(LFP) studies provide kinetics and activation parameters for the carbons fragmentations, which are orders of magnitude faster, and require considerably reduced activation energies, compared to analogous solvolytic carbocation-generative processes. In some cases, the time required for solvent and anion equilibration of the ion pairs can be estimated. In nonpolar solvents, the gas phase, or cryogenic matrices, homolytic carbons fragmentation may, in certain cases, supplant heterolytic fragmentation.