Tetrabutylammonium tetrahydroborate

Asymmetric 1,4-addition of various malonates to enones has been carried out using tetrabutylammonium tetrahydroborate (TBATB) in the presence of a chiral ligand.32 nB NMR spectroscopic studies have explained the unexpected reactivity through the... 

Tetrabutylammonium tetrahydroborate(l —) is a white, crystalline solid, moderately stable in air at room temperature. It is soluble in methylene chloride, chloroform, methanol, ethanol, water, tetrahydrofuran, and benzene, but insoluble in diethyl ether and pentane. Its H nmr spectrum consists of [N(n-C4H9)4] + multiplets centered at t6.73, t8.49, and t9.03 and a sharp 1 1 1 1 quartet (t 10.17, JBH = 82 Hz) characteristic of [BH4) . The nB nmr spectrum is similar to that of [P(C6H5)3CH3][BH4]. 

A commercially available solution of tetrabutylammonium hydroxide in methanol (30 mL of 31.4% [N( -C4H9)4]OH, 30.6 mmol) was added with stirring to a solution of 2.73 g (72.2 mmol) of sodium tetrahydroborate(l —) in 30 mL of 10% methanolic sodium hydroxide. The solution is stirred for... 

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