1302132-86-0Relevant articles and documents
Structure and reactivity of a preactivated sp2-sp3 diboron reagent: Catalytic regioselective boration of α,β-unsaturated conjugated compounds
Gao, Ming,Thorpe, Steven B.,Kleeberg, Christian,Slebodnick, Carla,Marder, Todd B.,Santos, Webster L.
experimental part, p. 3997 - 4007 (2011/06/27)
A novel sp2-sp3 diboron reagent has been developed for the copper-catalyzed β-boration of α,β-unsaturated conjugated compounds. The reaction proceeds under mild conditions with various substrates, i.e., α,β-unsaturated esters, ketones, nitriles, ynones, amides, and aldehydes, in the absence of additives such as phosphine and sodium tert-butoxide to provide β-borylhomoenolates in good to excellent yields. The presence of an sp3-hybridized boron center, unambigously confirmed by X-ray crystallography, sufficiently activates the unsymmetrical pinacolato diisopropanolaminato diboron (PDIPA diboron, 2) to transfer the sp2-hybridized boron moiety chemoselectively. These observations suggest that the activation of one of the boron atoms is an essential step in the Cu-catalyzed β-boration catalytic cycle.
