A simpleone-potprocedure for the direct reductive amination of aldehydes using lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) or a polymer supported naphthalene as reducing system is described. The direct reductive amination of a variety of aldehydes with primary amines was achieved simply by adding a mixture of the corresponding carbonyl compound and the amine, over a
Polyoxometalate catalyzed imine synthesis: Investigation of mechanistic pathways
作者:Subhasis D. Adhikary、Debaprasad Mandal
DOI:10.1016/j.tet.2020.131245
日期:2020.6
syntheses of imines by oxidative coupling of primary alcohols and amines were achieved by using 2 mol% polyoxometalate (POM) Na12[WZn3(H2O)2(ZnW9O34)2] (Zn–WZn3) catalyst in the presence of t-BuOK and di-oxygen with excellent conversion (up to 100%) and selectivity (up to 100%). Non-noble metal-based POM catalyst in the presence of base represents a new reaction protocol for the selective synthesis of imine
efficient precatalyst for the hydroboration of a wide variety of aldehydes, ketones, and imines at −10 °C. DFT calculations propose that hydroboration involves hydride transfer from the corresponding tin(II) hydride intermediate [Ph2P(NtBu)2]SnH (10) to the carbonyl substrates via four-membered transition states (TS-12), affording three-coordinated tin(II) alkoxide intermediates [Ph2P(NtBu)2]SnOR (13)
一种新型的三配位氯化锡 ( II ) [Ph 2 P(N t Bu) 2 ]SnCl ( 1 ) 由在磷原子上具有两个苯基的N , N '-二叔丁基亚氨基膦酰胺负载合成起始的亚氨基膦酰胺锂[Ph 2 P(N t Bu) 2 ]Li与SnCl 2 ·(二恶烷)在甲苯中的反应。的分子结构1通过X射线衍射分析确定。氯化锡( II ) 1可以作为一种有效的预催化剂,用于在 -10 °C 下对各种醛、酮和亚胺进行硼氢化反应。DFT 计算表明硼氢化反应涉及氢化物从相应的锡 ( II ) 氢化物中间体 [Ph 2 P(N t Bu) 2 ]SnH ( 10 )通过四元过渡态 ( TS-12 )转移到羰基底物,提供三个-配位锡( II )醇盐中间体[Ph 2 P(N t Bu) 2 ]SnOR ( 13 ),然后是13的逐步反应与 HBpin (pin = pinacolate) 释放硼酸酯和再生锡 ( II
Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst
作者:Frederik Freitag、Torsten Irrgang、Rhett Kempe
DOI:10.1021/jacs.9b05024
日期:2019.7.24
highly active and chemoselective manganese catalyst for the hydrogenation of imines. The catalyst has a large scope, can reduce aldimines and ketimines, and tolerates a variety of functional groups, among them hydrogenation sensitive examples such as an olefin, a ketone, nitriles, nitro groups and an aryl iodo substituent or a benzyl ether. We could investi-gate the transfer step between imines and the
我们介绍了一种用于亚胺加氢的高活性和化学选择性锰催化剂。该催化剂适用范围广,可还原醛亚胺和酮亚胺,可耐受多种官能团,其中对氢化敏感的例子如烯烃、酮、腈、硝基和芳基碘取代基或苄基醚。我们可以详细研究亚胺和氢化物配合物之间的转移步骤。我们发现配体的双重去质子化是必不可少的,过量的碱不会导致转移步骤中的更高速率。我们将实际的加氢催化剂鉴定为 K-Mn-双金属物种,并且可以通过 X 射线分析获得氢化物转移后形成的 K-Mn 配合物的结构。核磁共振实验表明氢化物转移是一个明确定义的反应,这是亚胺的一级,双金属(K-Mn)氢化物的一级,并且速率与钾碱的浓度无关。我们提出了一种外球机制,其中质子似乎不参与速率确定步骤,导致底物中的瞬态带负电荷的氮原子与 HOtBu(2-methylpropan-2-ol)迅速反应以产生胺。这是基于几个观察结果,例如反应速率不依赖于 HOtBu 浓度,没有可观察到的锰酰胺
<i>Z</i>-Stereoselective Aza-Peterson Olefinations with Bis(trimethylsilane) Reagents and Sulfinyl Imines
作者:Manas Das、Donal F. O’Shea
DOI:10.1021/acs.orglett.5b03519
日期:2016.1.15
Highlystereoselective aza-Peterson olefinations from bench-stable α,α-bis(trimethylsilyl)toluene reagents and N-substituted imines have been achieved using TMSO–/Bu4N+ as Lewis base activator in THF. Remarkably, and for the first time, N-t-butanesulfinyl imines were utilized for the synthesis of Z-stilbenes with excellent selectivities, while N-aryl imines generated E-stilbenes under identical reaction