Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: integrating nucleophilicity with Lewis acidic activation
作者:Mrinal Bhunia、Sumeet Ranjan Sahoo、Arpan Das、Jasimuddin Ahmed、Sreejyothi P.、Swadhin K. Mandal
DOI:10.1039/c9sc05953a
日期:——
potassium complex was used as a transitionmetal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis
Primary amides to amines or nitriles: a dual role by a single catalyst
作者:Hari S. Das、Shyamal Das、Kartick Dey、Bhagat Singh、Rahul K. Haridasan、Arpan Das、Jasimuddin Ahmed、Swadhin K. Mandal
DOI:10.1039/c9cc05856g
日期:——
of various primary amides to amines (25 examples). On simple modification of the reaction conditions such as in the presence of a catalytic amount of secondary amide, the same catalyst can transform the primary amides into intermediate nitrile compounds (16 examples) in excellent yields. This is the first example where such a controlled catalytic transformation of primary amides to amines or nitriles
Cobalt-Catalyzed and Lewis Acid-Assisted Nitrile Hydrogenation to Primary Amines: A Combined Effort
作者:Kenan Tokmic、Bailey J. Jackson、Andrea Salazar、Toby J. Woods、Alison R. Fout
DOI:10.1021/jacs.7b07368
日期:2017.9.27
The selective hydrogenation of nitriles to primary amines using a bench-stable cobalt precatalyst under 4 atm of H2 is reported herein. The catalyst precursor was reduced in situ using NaHBEt3, and the resulting Lewis acid formed, BEt3, was found to be integral to the observed catalysis. Mechanistic insights gleaned from para-hydrogen induced polarization (PHIP) transfer NMR studies revealed that the
本文报道了在 4 个大气压的 H 2 下使用实验室稳定的钴预催化剂将腈选择性氢化成伯胺。使用 NaHBEt 3 原位还原催化剂前体,并且发现所形成的路易斯酸 BEt 3 是观察到的催化作用的组成部分。从对氢诱导极化 (PHIP) 转移 NMR 研究中收集到的机理见解表明,腈的成对氢化是通过 Co(I/III) 氧化还原过程进行的。
A cobalt phosphide catalyst for the hydrogenation of nitriles
phosphide catalysts for organic synthesis is rare. We present, for the first time, a well-defined nano-cobalt phosphide (nano-Co2P) that can serve as a new class of catalysts for the hydrogenation of nitriles to primary amines. While earth-abundant metal catalysts for nitrile hydrogenation generally suffer from air-instability (pyrophoricity), low activity and the need for harsh reaction conditions
用于有机合成的金属磷化物催化剂的研究很少。我们首次提出了一种定义明确的纳米钴磷化物 (nano-Co 2 P),它可以作为一种新型催化剂,用于将腈类氢化成伯胺。虽然用于腈加氢的地球上丰富的金属催化剂通常具有空气不稳定性(自燃性)、低活性和需要苛刻的反应条件,但 nano-Co 2 P 显示出空气稳定性和非常高的戊腈加氢活性。优秀的营业额超过 58000,比之前报道的高出 20 到 500 倍以上。此外,纳米Co 2即使在仅 1 bar 的 H 2压力下, P 也能有效地促进多种腈(包括二腈和四腈)氢化成相应的伯胺,远比常规反应条件温和。详细的光谱研究表明,纳米 Co 2 P的高性能归因于其空气稳定的金属性质,以及通过钴的磷化作用使 Co 在费米能级附近的 d 电子密度增加,从而导致加速腈和H 2的活化。这种磷化为设计在高效和环境友好的氢化中具有高活性和稳定性的先进催化剂提供了一种有前景的方法。
Boron-Catalyzed Silylative Reduction of Nitriles in Accessing Primary Amines and Imines
Silylative reduction of nitriles was studied under transition metal-free conditions by using B(C6F5)3 as a catalyst with hydrosilanes as a reductant. Alkyl and (hetero)aryl nitriles were efficiently converted to primaryamines or imines under mild conditions. The choice of silanes was found to determine the selectivity: while a full reduction of nitriles was highly facile, the use of sterically bulky
在无过渡金属的条件下,通过使用B(C 6 F 5)3作为催化剂,以氢硅烷作为还原剂,研究了腈的甲硅烷基化还原反应。在温和的条件下,烷基和(杂)芳基腈被有效地转化为伯胺或亚胺。发现硅烷的选择决定了选择性:虽然腈的完全还原非常容易,但是使用空间大体积的硅烷允许部分还原,从而生成N-甲硅烷基亚胺。