In organic chemistry the Brook rearrangement refers to any [1,n] carbon to oxygen silyl migration. The rearrangement was first observed in the late 1950s by Canadian chemist Adrian Gibbs Brook (1924–2013), after which the reaction is named.[1] These migrations can be promoted in a number of different ways, including thermally, photolytically or under basic/acidic conditions.[2] In the forward direction, these silyl migrations produce silyl ethers as products which is driven by the stability of the oxygen-silicon bond.
The silyl substituents can be aliphatic or aromatic, and if the silicon is a center of chirality, the migration occurs with retention at this center. This migration occurs through a transition state where silicon is penta-coordinate and bears a partial negative charge.[3] If a center of chirality is present at the carbon center to which the silyl group is attached, then inversion occurs at this center. As an example, if (trimethylsilyl)methanol where to be deprotonated, a [1,2]-Brook rearrangement would occur.
- ^ Brook, A. G. (1958). "Isomerism of some α-hydroxysilanes to silyl ethers". J. Am. Chem. Soc. 80 (8): 1886–1889. doi:10.1021/ja01541a026.
- ^ Brook, A. G.; Bassindale, A. R. (1980). "Chapter 9. Molecular rearrangements of organosilicon compounds". Rearrangements in Ground and Excited States, Vol 2. New York: Academic Press. pp. 149–221. ISBN 9781483218724.
- ^ Brook, A. G. (1974). "Molecular rearrangements of organosilicon compounds". Acc. Chem. Res. 7 (3): 77–84. doi:10.1021/ar50075a003.