Dehydrocoupling Reactions of Borane−Secondary and −Primary Amine Adducts Catalyzed by Group-6 Carbonyl Complexes: Formation of Aminoboranes and Borazines
solution of BH(3).NHR(2) (1a: R = Me, 1b: R = 1/2C(4)H(8), 1c: R = 1/2C(5)H(10), 1f: R = Et) containing a catalytic amount of a group-6 metal carbonyl complex, [M(CO)(6)] (M = Cr, Mo, W), led to dehydrogenative B-N covalent bond formation to produce aminoborane dimers, [BH(2)NR(2)](2) (2a-c, f), in high yield. During these reactions a borane sigma complex, [M(CO)(5)(eta(1)-BH(3).NHR(2))] (3), was detected
Homogeneous Catalytic Dehydrocoupling/Dehydrogenation of Amine−Borane Adducts by Early Transition Metal, Group 4 Metallocene Complexes
作者:Matthew E. Sloan、Anne Staubitz、Timothy J. Clark、Christopher A. Russell、Guy C. Lloyd-Jones、Ian Manners
DOI:10.1021/ja909535a
日期:2010.3.24
The efficient catalytic dehydrocoupling of a range of amine-borane adducts, R'RNH x BH(3) (R' = R = Me 1a; R' = R = (i)Pr 1b; R' = Me, R = CH(2)Ph 1c) by a series of group 4 metallocene type precatalysts has been demonstrated. A reduction in catalytic activity was detected upon descending the group and also on substitution of the cyclopentadienyl (Cp) ligands with sterically bulky or electron-donating
Synthetic and mechanistic studies of metal-free transfer hydrogenations applying polarized olefins as hydrogen acceptors and amine borane adducts as hydrogen donors
作者:Xianghua Yang、Thomas Fox、Heinz Berke
DOI:10.1039/c1ob06381b
日期:——
spectroscopy. Deuterium kinetic isotope effects and the traced hydroboration intermediate revealed that the double H transfer process occurred regio-specifically in two steps with hydride before proton transfer characteristics. Studies on substituent effects and Hammett correlation indicated that the rate determining step of the HN transfer is in agreement with a concertedtransitionstate. The very reactive intermediate
极化烯烃的无金属转移氢化(RR'C CEE':R,R'= H或有机基,E,E'= CN或 CO 2我)使用胺硼烷加合物 RR'NH–BH 3(R = R'= H,AB ; R = Me,R'= H,人与生物圈; R = t Bu,R'= H,tBAB; R = R′=我,DMAB通过原位NMR光谱研究作为氢供体的H 2O。氘 动力学同位素效应和所追踪的硼氢化中间体表明,双H转移过程在两个步骤中都发生了区域特异性反应 氢化物质子转移前的特征。对取代基效应和Hammett相关性的研究表明,^ h ñ转移与一致的过渡状态相一致。由AB生成的非常活泼的中间体[NH 2 BH 2 ]通过添加二甲醚被捕集环己烯 进入反应混合物形成 Cy 2 BNH 2。最终产品硼嗪假定(BHNH)3是通过[NH 2 BH 2 ]或其溶剂稳定的衍生物[NH 2 BH 2 ]-(溶剂)脱氢偶联形成的,而不是通过环三硼烷[NH
Reactions of Amine– and Phosphane–Borane Adducts with Frustrated Lewis Pair Combinations of Group 14 Triflates and Sterically Hindered Nitrogen Bases
作者:George R. Whittell、Edward I. Balmond、Alasdair P. M. Robertson、Sanjib K. Patra、Mairi F. Haddow、Ian Manners
DOI:10.1002/ejic.201000515
日期:2010.9
amine- and phosphane―borane adducts has been investigated. By using multinuclear NMR spectroscopy, it has been shown that Me 2 NH·BH 3 (11) is efficiently converted to [Me 2 N―BH 2 ] 2 (12) by the so-called "frustrated Lewis pair" (FLP) of nBu 3 SnOTf (4, ― OTf = ― OSO 2 CF 3 ) and 2,2,6,6-tetramethylpiperidine (6). Within the scope of the study, exchange of the Lewis acid effects the rate of dehydrogenation
Amine‐Borane Dehydrogenation and Transfer Hydrogenation Catalyzed by α‐Diimine Cobaltates
作者:Thomas M. Maier、Sebastian Sandl、Ilya G. Shenderovich、Axel Jacobi von Wangelin、Jan J. Weigand、Robert Wolf
DOI:10.1002/chem.201804811
日期:2019.1.2
catalyze the dehydrogenation of several amine‐boranes. Based on the excellent catalytic properties, an especially effective transfer hydrogenation protocol for challenging olefins, imines, and N‐heteroarenes was developed. NH3BH3 was used as a dihydrogen surrogate, which transferred up to two equivalents of H2 per NH3BH3. Detailed spectroscopic and mechanisticstudies are presented, which document the rate