boraneether

Boraneether refers to a class of coordination complexes formed between borane (BH3) and ether ligands. In these adducts, a lone pair on the ether oxygen donates to the empty orbital on boron, creating a Lewis acid–base interaction that stabilizes borane as BH3–ether adducts. The most common examples are borane–tetrahydrofuran, BH3·THF, and borane–diethyl ether, BH3·Et2O. These adducts are typically blocky, air- and moisture-sensitive reagents used as convenient sources of borane in chemical synthesis.

Structure and properties are governed by the donor strength of the ether. In the adduct, boron becomes four-coordinate with a quasi-tetrahedral geometry, and the complex behaves as a stabilized form of borane, reducing its tendency to dimerize to B2H6 in coordinating solvents. The BH3–ether interaction is relatively labile; the ether ligand can be displaced by stronger donors or by heating, releasing free BH3 when needed for reactivity.

Preparation and handling are straightforward yet require inert conditions. BH3–ether adducts are typically prepared by combining a borane source with the desired ether in an appropriate solvent, or by using commercially available BH3·THF or BH3·SMe2 and allowing solvent exchange with other ethers. Because borane reagents are highly reactive toward water and oxygen, they are usually stored and used under inert atmosphere.

Applications center on borane delivery for hydroboration and related transformations. BH3–ether adducts serve as practical, controllable sources of BH3 for hydroboration of alkenes and alkynes, followed by oxidation to furnish alcohols or other organoboron derivatives. They are valued for their solubility, handling characteristics, and compatibility with a range of substrates.