Dichloroborane Diethyl Etherate

Abstract

[41156-66-5] C4H11BCl2O (MW 156.85) InChI = 1S/C4H10O.BCl2H/c1-3-5-4-2;2-1-3/h3-4H2,1-2H3;1H InChIKey = WNSLVZYKMLFZRE-UHFFFAOYSA-N (hydroborating agent providing access to alkyldichloroboranes and alkenyldichloroboranes;2 reagent for deoxygenation of sulfoxides3 and cleavage of cyclic acetals4) Physical Data: bp 59 °C/1.5 mmHg;5 mp −30 to −25 °C.6, 7 Solubility: sol benzene, carbon tetrachloride, diethyl ether; not miscible with pentane. Analysis of Reagent Purity: the hydride content is determined by hydrolyzing an aliquot and measuring the hydrogen evolved according to the standard procedure.8 The chloride is estimated by hydrolyzing an aliquot and titrating the HCl produced with NaHCO3 using methyl orange as indicator. Coulometric titration has also been used for the determination of BHCl2·OEt2.9a 11B NMR: δ, ppm 8.1;9b 7.9 (JBH = 152 Hz).9c Preparative Methods: an approximately 1.5 M solution in diethyl ether can be prepared by the reaction of Lithium Borohydride with Boron Trichloride.2 The neat reagent can be isolated by removing excess diethyl ether. It is a colorless liquid, 6.6 M in BHCl2, containing about 4–6 mol % of BCl3·OEt2 as impurity. Less conveniently, BHCl2·OEt2 can also be prepared by reacting BCl3 with Diborane in the presence of diethyl ether.6, 7 The deuterated reagent is known.7 Handling, Storage, and Precautions: corrosive, flammable, air- and moisture-sensitive liquid. Reacts violently with water. The reagent is not stable over long periods of time, cleaving the ether solvent at a significant rate, even with storage at 0 °C. The neat reagent is not stable for more than 2 days at rt. Handle in a fume hood.