Activation of sodium borohydride <i>via</i> carbonyl reduction for the synthesis of amine- and phosphine-boranes
作者:P. Veeraraghavan Ramachandran、Henry J. Hamann、Randy Lin
DOI:10.1039/d1dt03495b
日期:——
carbonyl reduction by sodiumborohydride is described. Unlike the prior bicarbonate-mediated protocol, which proceeds via a salt metathesis reaction, the carbon dioxide-mediated synthesis proceeds via reduction to a monoformatoborohydride intermediate. This has been verified by spectroscopic analysis, and by using aldehydes and ketones as the carbonyl source for the activation of sodiumborohydride. This
Direct preparation and structure determination of tertiary and secondary amine boranes from primary or secondary amine boranes
作者:Amal Shibli、Hijazi Abu Ali、Israel Goldberg、Morris Srebnik
DOI:10.1016/j.jorganchem.2005.01.059
日期:2005.4
New secondary and tertiary amine borane derivatives were prepared in a one-pot reaction starting fromprimaryamine boranes. The reaction involves treatment of an amine borane with 2 equivalents of s-BuLi at −78 °C. In general, mixtures of mono and di metallated products were obtained. Alkyl iodides and benzyl chloride reacted with the lithiated amine, but aldehydes and ketones were reduced. Conversion
Electrophilic C–H Borylation and Related Reactions of B–H Boron Cations
作者:Aleksandrs Prokofjevs、Janis Jermaks、Alina Borovika、Jeff W. Kampf、Edwin Vedejs
DOI:10.1021/om400651p
日期:2013.11.25
Catalytic procedures are described for the amine-directed borylation of aliphatic and aromatic tertiary amine–boranes. Sequential double borylation is observed in cases where two or more C–H bonds are available that allow 5-center or 6-center intramolecular borylation. The HNTf2-catalyzed borylation of benzylamine–boranes provides a practical means for the synthesis of ortho-substituted arylboronic
Effects of amine-borane structure on the stoichiometry, rate and mechanism of reaction with hypochlorous acid: hydride oxidation versus B-chlorination
作者:Kevin E. Bell、Curtis R. Kelly、David E. Minter、Henry C. Kelly
DOI:10.1016/s0020-1693(00)85601-7
日期:1993.9
involve bimolecular rate-limiting attack of HOCl on amine-borane with different intimate mechanisms arising from correspondingly different activated complexes. A low reactivity of quinoline-monochloroborane with hypochlorite precludes the involvement of a chloroborane as a common intermediate in both processes. The activation free-energy for chlorination of trimethylamine-borane is higher than δ G ≠ values
摘要各种环取代的苄胺-硼烷以及α-甲基和N-甲基苄胺-硼烷与NaOCl反应进行氢化物氧化和N-氯化反应,而N,N-二甲基苄胺-硼烷经过B-氯化反应生成胺混合物。氯硼烷。结果与先前确定的与被氧化的烷基和非芳族杂环仲胺-硼烷以及它们的三级对应物进行B-氯化反应的反应模式一致。当前的研究表明,喹啉系列中叔胺的硼烷加合物通过氧化途径发生反应。环或α-甲基取代对苄胺-硼烷氧化速率的影响可忽略不计,而N-甲基取代引起的三倍降低。苄胺-硼烷反应显示出适度的底物同位素效应(k BH3 / k BD3≅1.3),明显的逆溶剂同位素效应(k D2O / k H 2 O 3)和速率的pH依赖性,表明饱和动力学低于pH 7.5 。建议氧化和B-氯化都涉及HOCl对胺-硼烷的双分子限速攻击,其具有由相应不同的活化复合物引起的不同的密切机制。喹啉-一氯硼烷与次氯酸盐的低反应性排除了氯硼烷作为两种方法的常见中间体。三甲
Thermal Dehydrogenation of Base‐Stabilized B
<sub>2</sub>
H
<sub>5</sub>
<sup>+</sup>
Complexes and Its Role in CH Borylation
作者:Aleksandrs Prokofjevs
DOI:10.1002/anie.201507647
日期:2015.11.2
dehydrogenation of the H‐bridged cation L2B2H5+ (L=Lewis base) is proposed to be the key step in the intramolecular CH borylation of tertiary amineboranes activated with catalytic amounts of strong “hydridophiles”. Loss of H2 from L2B2H5+ generates the highly reactive cation L2B2H3+, which in its sp2‐sp3 diborane(4) form then undergoes either an intramolecular CHinsertion with BBbond cleavage, or captures
H桥阳离子L 2 B 2 H 5 +(L=路易斯碱)的热诱导脱氢被认为是用催化量的强“亲水剂”活化的叔胺硼烷分子内C - H硼基化的关键步骤。L 2 B 2 H 5 +失去 H 2生成高反应性阳离子 L 2 B 2 H 3 +,其 sp 2 ‐sp 3乙硼烷 (4) 形式随后经历分子内 C H 插入和 B B键断裂,或捕获BH 3产生L 2 B 3 H 6 +。通过L 2 B 2 H 5 + HB(C 6 F 5 ) 3 -歧化形成LBH 2 C 6 F 5络合物说明抗衡离子稳定性对反应结果的影响。