Regiocontrolled Opening of Cyclic Ethers Using Dimethylboron Bromide

Article abstract of DOI:10.1021/jo00385a007

The cleavage of various cyclic ethers (3- to 7-membered rings) was achieved under very mild conditions using dimethylboron bromide to afford the corresponding bromo alcohols.In particular, 2-substituted tetrahydrofurans were regioselectively cleaved by a predominantly S_N2 - type mechanism favoring the formation of primary vs. secondary bromides.Dimethylboron bromide also cleaved chemoselectively substituted tetrahydrofurans in the presence of functional groups such as acyclic ethers, silyl ethers, esters, amides, ketones,etc.