ChemicalBook CAS DataBase List BUTYLDICHLOROBORANE

BUTYLDICHLOROBORANE synthesis

11synthesis methods

Product Name:BUTYLDICHLOROBORANE
CAS Number:14090-22-3
Molecular formula:C4H9BCl2
Molecular Weight:138.83

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Yield:-

Reaction Conditions:

Stage #1: tributyl boranewith borane-THF in tetrahydrofuran at 22; for 0.5 h;Inert atmosphere;
Stage #2: with boron trichloride at 100; for 2 h;Inert atmosphere;

Steps:

neat n-butyldichloroborane

A 100 mL Schlenk flask was flame-dried under high vacuum and then cooled to rt undera stream of Ar. The flask was charged with neat tributylborane (7) (11.8 mL, 48.4 mmol, 1.0 equiv.) and then BH3-THF complex (1.0 M in THF, 2.4 mL, 2.4 mmol, 0.05 equiv.) was added dropwise. The resulting solution was stirred at room temperature for 30 min and then the THF was removed in vacuo (< 0.1 mm Hg) for 10 min. The flask was flushed with Ar and then was topped with a dry ice condenser. The reaction setup was evacuated and back-filled with Ar (x3). The mixture was heat to 100 °C (bath temp.) and the condenser was filled with dry ice/acetone. BCl3 gas (~11 mL, 125 mmol, 2.6 equiv.) was then condensed slowly into the reaction mixture. After the addition was complete the reaction mixture was stirred at 100 °C for 2 h (maintaining the condenser temp. at ~ -78 °C ). 1-Hexene (6.0 mL, 48.3 mmol, 1.0 equiv.) was added and the reaction was stirred at the same temperature for an addition 30 min. The solution was cooled to rt and the condenser was replaced with a 6” vigreux column topped with a short-path fractional distillation apparatus. Unreacted BCl3 was removed from the reaction flask at 375 mm Hg and collected in a cold trap (cooled with liquid N2). Fractional distillation was then carried out at 120 mm Hg and n-butyldichloroborane was collected at 45-51 °C as a colorless, highly pyrophoric liquid (yield not determined)

References:

Hughes, Jonathan M.E.;Gleason, James L. [Tetrahedron,2018,p. 759 - 768] Location in patent:supporting information