Hydroboration of aldehydes, ketones and CO<sub>2</sub> under mild conditions mediated by iron(<scp>iii</scp>) salen complexes
作者:Samantha Lau、Cei B. Provis-Evans、Alexander P. James、Ruth L. Webster
DOI:10.1039/d1dt02092g
日期:——
The hydroboration of aldehydes, ketones and CO2 is demonstrated using a cheap and air stable [Fe(salen)]2-μ-oxo pre-catalyst with pinacolborane (HBpin) as the reductant under mild conditions. This catalyst system chemoselectively hydroborates aldehydes over ketones and ketones over alkenes. In addition, the [Fe(salen)2]-μ-oxo pre-catalyst shows good efficacy at reducing “wet” CO2 with HBpin at room
A Bottleable Imidazole-Based Radical as a Single Electron Transfer Reagent
作者:Arpan Das、Jasimuddin Ahmed、N. M. Rajendran、Debashis Adhikari、Swadhin K. Mandal
DOI:10.1021/acs.joc.0c02465
日期:2021.1.1
4-diphenyl-1H-imidazol-3-ium chloride (1) resulted in the formation of the first structurally characterized imidazole-based radical 2. 2 was established as a single electrontransferreagent by treating it with an acceptor molecule tetracyanoethylene. Moreover, radical 2 was utilized as an organic electron donor in a number of organic transformations such as in activation of an aryl–halide bond, alkene hydrosilylation
Metal-free disproportionation of formic acid mediated by organoboranes
作者:Clément Chauvier、Pierre Thuéry、Thibault Cantat
DOI:10.1039/c6sc01410k
日期:——
In the presence of dialkylboranes, formic acid can be converted to formaldehyde and methanol derivatives without the need for an external reductant. This reactivity, in which formates serve as the sole carbon and hydride sources, represents the first example of the disproportionation of formate anions under metal-free conditions. Capitalizing on both experimental and computational (DFT) mechanistic
Ethyloboration of Selenium Dioxide and Selenium Bis(
<i>tert</i>
‐butylimide) – Molecular Structure of an Organo‐Substituted Eight‐Membered [–BOSeO–]
<sub>2</sub>
Heterocycle
Both seleniumdioxide (1) and seleniumbis(tert-butylimide) (2) react with triethylborane (A) by 1,2-ethyloboration. In the case of 1, ethane, ethene, diethylselane (4a), tetraethyldiboroxane (Et2B)2O (B), triethylboroxine (EtBO)3 (D) and a cyclic compound [–Et2BOSe(Et)O–]2 (52) are formed after heating to 65°C. Compound 52 is also formed when 1 reacts with B. Treatment of selenous acid (3) with A
Catalytic properties of nickel bis(phosphinite) pincer complexes in the reduction of CO2 to methanol derivatives
作者:Sumit Chakraborty、Yogi J. Patel、Jeanette A. Krause、Hairong Guan
DOI:10.1016/j.poly.2011.04.030
日期:2012.1
however, it reacts with 9-borabicyclo[3.3.1]nonane and pinacolborane to generate a methanol derivative and a boryl formate species, respectively. The catalytic reduction of CO 2 with catecholborane is more effectively catalyzed by a more sterically hindered nickel pincer hydride complex with bulky R groups on the phosphorus donor atoms. The nickel pincer hydride complexes are inactive catalysts for
摘要用间苯二酚ClP(C 5 H 9)在一个罐中制备了一种新的镍双(亚膦酸酯)夹钳络合物[2,6-(R 2 PO)2 C 6 H 3] NiCl(LR NiCl,R =环戊基) )2,NiCl 2和4-二甲基氨基吡啶。该夹钳化合物与LiAlH 4的反应产生氢化镍配合物,其能够在室温下快速还原CO 2以得到甲酸镍配合物。两种相关的甲酸镍配合物LR NiOCHO(R =环戊基和异丙基)的X射线结构显示了甲酰基相对于配位平面的“面内”构象。甲酸镍配合物LR NiOCHO(R =环戊基,异丙基和叔丁基)与儿茶酚硼烷的化学计量反应表明,庞大的R基团有助于该反应。LR NiOCHO(R =叔丁基)在室温下不与PhSiH 3反应;但是,它会与9-borabicyclo [3.3.1]壬烷和频哪醇硼烷反应,分别生成甲醇衍生物和甲酸硼基酯。邻苯二酚硼烷对CO 2的催化还原作用更有效地由位阻更大的磷供体原子上