H. Brown, J. Kanth, M. Zaidlewicz
Mar 11, 1999
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0
Influential Citations
6
Citations
Journal
Organometallics
Abstract
N,N-Diisopropyl-N-isobutylamine (1) forms a stable liquid borane adduct (4.7 M in BH3), when diborane is bubbled into the neat amine. The adduct thus formed is stable indefinitely at room temperature under an inert atmosphere. Hydroboration studies with this new, highly reactive amine−borane adduct, H3B:NPri2Bui (2) and representative olefins, such as 1-hexene, styrene, β-pinene, cyclopentene, norbornene, cyclohexene, 2-methyl-2-butene, α-pinene, and 2,3-dimethyl-2-butene, were carried out at room temperature (22 ± 3 °C) in selected solvents, tetrahydrofuran, dioxane, tert-butyl methyl ether, n-pentane, and dichloromethane. The reactions are faster in dioxane and n-pentane, requiring ∼2 h for the hydroboration of simple, unhindered olefins to the trialkylborane stage. Moderately hindered olefins, such as cyclohexene and 2-methyl-2-butene, give the corresponding dialkylboranes rapidly, with further hydroboration to the trialkylborane stage slower. However, the hindered α-pinene and 2,3-dimethyl-2-butene st...