Dyotropic reaction

A dyotropic reaction (from the Greek dyo, meaning two) in organic chemistry is a type of organic reaction and more specifically a pericyclic valence isomerization in which two sigma bonds simultaneously migrate intramolecularly.

It was first described by Manfred T. Reetz in 1971 [2][3] In a type I reaction two migrating groups interchange their relative positions and a type II reaction involves migration to new bonding sites without positional interchange.

The first example of a dyotropic rearrangement involving a carbon-carbon bond was reported by Cyril A. Grob and Saul Winstein.

Type I dyotropic rearrangements also occur around carbon-oxygen bonds, such as the thermal equilibration of (R3Si1)R2C-O-Si2R3 to (R3Si2)R2C-O-Si1R3.

Type II rearrangements often involve double hydrogen migration in a carbon skeleton.