perform as an efficient heterogeneous catalyst for the synthesis of useful organoboron compounds. Desired β-borylation products were all obtained in good to excellent yields under mild conditions. This catalyst could be recovered easily and still work effectively in six runs. Notably, asymmetric synthesis of organoboron compounds was accomplished by applying a chiral phosphine ligand. This newly developed
sp<sup>2</sup>−sp<sup>3</sup> Hybridized Mixed Diboron: Synthesis, Characterization, and Copper-Catalyzed β-Boration of α,β-Unsaturated Conjugated Compounds
作者:Ming Gao、Steven B. Thorpe、Webster L. Santos
DOI:10.1021/ol901359n
日期:2009.8.6
A novel sp2−sp3 hybridized mixed diboron and its reactivity on the copper-catalyzed β-boration of α,β-unsaturated conjugated compounds to afford the corresponding β-borated compounds is reported. The presence of sp3-hybridized boron provides a mild β-boration condition in the absence of phosphine and base additives. Finally, our investigations demonstrate that the sp2-hybridized boron of the mixed
Conjugated aldehydes and ketones undergo reaction with Me2PhSiBpin (pin: pinacolato) catalyzed by Au nanoparticles supported on TiO2 forming exclusively the β-borylation products, via the intermediate formation of the labile silaboration adducts. This chemoselectivity pathway is complementary to the so far known analogous reaction catalyzed by other metals, where β-silylation occurs instead. β-Borylation
Addition and Coupling Reactions of Bis(pinacolato)diboron Mediated by CuCl in the Presence of Potassium Acetate
作者:Kou Takahashi、Tatsuo Ishiyama、Norio Miyaura
DOI:10.1246/cl.2000.982
日期:2000.9
The addition of bis(pinacolato)diboron [(Me4C2O2)B-B(O2C2Me4)] to α,β-unsaturated ketones, esters, nitriles, or terminal alkynes and the coupling with allyl chlorides were carried out in DMF at room temperature in the presence of CuCl and AcOK. The transmetalation from boron to copper generating a B–Cu species was proposed as the key step of the reactions.
Ligandless Copper-Catalyzed β-Boration of α,β-Unsaturated Compounds in Aqueous Solution
作者:Hee-Sung Chea、Hak-Suk Sim、Jae-Sook Yun
DOI:10.5012/bkcs.2010.31.03.551
日期:2010.3.20
water as a co-solvent and a reaction promoter exerted a positive effect on catalytic efficiency and resulted in the efficient β-boration of α,β-unsaturated carbonyl compounds including substituted enones and esters. This new, operationally simple method is useful for the preparation of racemic organoboron compounds.Our investigation of the borationreaction under ligand-free conditions began with β-monosubstituted