Wang Jin, Ju Ming-Yue, Wang Xinghua, Ma Yan-Na, Wei Donghui, Chen Xuenian
School of Chemistry and Chemical Engineering, Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, Henan Normal University, Xinxiang 453007, China.
College of Chemistry and Chemical Engineering, Mudanjiang Normal University, Mudanjiang 157011, China.
J Org Chem. 2021 Apr 2;86(7):5305-5316. doi: 10.1021/acs.joc.1c00302. Epub 2021 Mar 17.
Hydroboration reactions of carboxylic acids using sodium aminodiboranate (NaNH[BH], NaADBH) to form primary alcohols were systematically investigated, and the reduction mechanism was elucidated experimentally and computationally. The transfer of hydride ions from B atoms to C atoms, the key step in the mechanism, was theoretically illustrated and supported by experimental results. The intermediates of NHBH, PhCH═CHCOOBHNHBH, PhCH═CHCHOBO, and the byproducts of BH, NHBH, and NHBH were identified and characterized by B and H NMR. The reducing capacity of NaADBH was found between that of NaBH and LiAlH. We have thus found that NaADBH is a promising reducing agent for hydroboration because of its stability and easy handling. These reactions exhibit excellent yields and good selectivity, therefore providing alternative synthetic approaches for the conversion of carboxylic acids to primary alcohols with a wide range of functional group tolerance.
系统研究了使用氨基二硼酸钠（NaNH[BH]，NaADBH）将羧酸进行硼氢化反应以形成伯醇的过程，并通过实验和计算阐明了还原机理。从硼原子到碳原子的氢负离子转移是该机理中的关键步骤，从理论上进行了说明并得到了实验结果的支持。通过硼和氢的核磁共振对NHBH、PhCH═CHCOOBHNHBH、PhCH═CHCHOBO的中间体以及BH、NHBH和NHBH的副产物进行了鉴定和表征。发现NaADBH的还原能力介于NaBH和LiAlH之间。因此我们发现，由于NaADBH的稳定性和易于操作，它是一种很有前景的用于硼氢化反应的还原剂。这些反应具有优异的产率和良好的选择性，因此为将羧酸转化为具有广泛官能团耐受性的伯醇提供了替代合成方法。
