IX. Group Migration
- Page ID
- 23827
Acyl, silyl, phosphatoxy, phenyl, and cyano groups all are capable of undergoing group migration. Because in most reactions these groups are stable substituents and often act as protecting groups, migration is an event that depends not only on reaction conditions but also on the substrate having a particular type of structure. Sometimes it is unclear whether group migration is an elementary reaction or a combination of elementary reactions. The silyl group migration pictured in Scheme 7 is thought to be an elementary reaction, but it is possible that this process consists of a pair of reactions, β‑fragmentation and radical cyclization (Scheme 8).44 The group migration shown in eq 5945 appeared at first to be an elementary reaction, but extensive investigation has shown that it consisted of heterolytic fragmentation followed by ionic recombination (Scheme 9).46–48