- Phosphine-Free Manganese Catalyst Enables Selective Transfer Hydrogenation of Nitriles to Primary and Secondary Amines Using Ammonia-Borane
-
Herein we report the synthesis of primary and secondary amines by nitrile hydrogenation, employing a borrowing hydrogenation strategy. A class of phosphine-free manganese(I) complexes bearing sulfur side arms catalyzed the reaction under mild reaction conditions, where ammonia-borane is used as the source of hydrogen. The synthetic protocol is chemodivergent, as the final product is either primary or secondary amine, which can be controlled by changing the catalyst structure and the polarity of the reaction medium. The significant advantage of this method is that the protocol operates without externally added base or other additives as well as obviates the use of high-pressure dihydrogen gas required for other nitrile hydrogenation reactions. Utilizing this method, a wide variety of primary and symmetric and asymmetric secondary amines were synthesized in high yields. A mechanistic study involving kinetic experiments and high-level DFT computations revealed that both outer-sphere dehydrogenation and inner-sphere hydrogenation were predominantly operative in the catalytic cycle.
- Sarkar, Koushik,Das, Kuhali,Kundu, Abhishek,Adhikari, Debashis,Maji, Biplab
-
p. 2786 - 2794
(2021/03/03)
-
- Regio- and stereoselective hydroamination of alkynes using an ammonia surrogate: Synthesis of N -Silylenamines as reactive synthons
-
An anti-Markovnikov selective hydroamination of alkynes with N-silylamines to afford N-silylenamines is reported. The reaction is catalyzed by a bis(amidate)bis(amido)Ti(IV) catalyst and is compatible with a variety of terminal and internal alkynes. Stoichiometric mechanistic studies were also performed. This method easily affords interesting N-silylenamine synthons in good to excellent yields and the easily removable silyl protecting group enables the catalytic synthesis of primary amines.
- Lui, Erica K. J.,Brandt, Jason W.,Schafer, Laurel L.
-
supporting information
p. 4973 - 4976
(2018/04/24)
-
- Synthesis of cobalt nanoparticles by pyrolysis of Vitamin B12: A non-noble-metal catalyst for efficient hydrogenation of nitriles
-
A facile preparation of vitamin B12-derived carbonaceous cobalt particles supported on ceria is reported. The resulting composite material is obtained upon wet impregnation of ceria with natural cyanocobalamin and consecutive pyrolysis under inert conditions. The novel catalyst shows good to excellent performance in the industrially relevant heterogeneous hydrogenation of nitriles to the corresponding primary amines.
- Ferraccioli, Raffaella,Borovika, Diana,Surkus, Annette-Enrica,Kreyenschulte, Carsten,Topf, Christoph,Beller, Matthias
-
p. 499 - 507
(2018/02/07)
-
- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Polysilane/SiO2-Supported Palladium Catalyst under Continuous-Flow Conditions
-
Hydrogenation of nitriles to primary amines with heterogeneous catalysts under liquid-phase continuous-flow conditions is described. Newly developed polysilane/SiO2-supported Pd was found to be an effective catalyst and various nitriles were converted into primary amine salts in almost quantitative yields under mild reaction conditions. Interestingly, a complex mixture was obtained under batch conditions. Lifetime experiments showed that this catalyst remained active for more than 300 h (TON≥10 000) without loss of selectivity and no metal leaching from the catalyst occurred. By using this continuous-flow hydrogenation, synthesis of venlafaxine, an antidepressant drug, has been accomplished.
- Saito, Yuki,Ishitani, Haruro,Ueno, Masaharu,Kobayashi, Shū
-
p. 211 - 215
(2017/04/21)
-
- Selective Catalytic Hydrogenations of Nitriles, Ketones, and Aldehydes by Well-Defined Manganese Pincer Complexes
-
Hydrogenations constitute fundamental processes in organic chemistry and allow for atom-efficient and clean functional group transformations. In fact, the selective reduction of nitriles, ketones, and aldehydes with molecular hydrogen permits access to a green synthesis of valuable amines and alcohols. Despite more than a century of developments in homogeneous and heterogeneous catalysis, efforts toward the creation of new useful and broadly applicable catalyst systems are ongoing. Recently, Earth-abundant metals have attracted significant interest in this area. In the present study, we describe for the first time specific molecular-defined manganese complexes that allow for the hydrogenation of various polar functional groups. Under optimal conditions, we achieve good functional group tolerance, and industrially important substrates, e.g., for the flavor and fragrance industry, are selectively reduced.
- Elangovan, Saravanakumar,Topf, Christoph,Fischer, Steffen,Jiao, Haijun,Spannenberg, Anke,Baumann, Wolfgang,Ludwig, Ralf,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 8809 - 8814
(2016/07/29)
-
- Stable and Inert Cobalt Catalysts for Highly Selective and Practical Hydrogenation of C≡N and C=O Bonds
-
Novel heterogeneous cobalt-based catalysts have been prepared by pyrolysis of cobalt complexes with nitrogen ligands on different inorganic supports. The activity and selectivity of the resulting materials in the hydrogenation of nitriles and carbonyl compounds is strongly influenced by the modification of the support and the nitrogen-containing ligand. The optimal catalyst system ([Co(OAc)2/Phenα-Al2O3]-800 = Cat. E) allows for efficient reduction of both aromatic and aliphatic nitriles including industrially relevant dinitriles to primary amines under mild conditions. The generality and practicability of this system is further demonstrated in the hydrogenation of diverse aliphatic, aromatic, and heterocyclic ketones as well as aldehydes, which are readily reduced to the corresponding alcohols.
- Chen, Feng,Topf, Christoph,Radnik, J?rg,Kreyenschulte, Carsten,Lund, Henrik,Schneider, Matthias,Surkus, Annette-Enrica,He, Lin,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 8781 - 8788
(2016/08/02)
-
- A practical procedure for reduction of primary, secondary and tertiary amides to amines
-
A mild and general procedure for reduction of primary, secondary, and tertiary amides using catalytic triruthenium dodecacarbonyl and 1,1,3,3-tetramethyldisiloxane as reductant is described. The reaction is tolerant of numerous functional groups, and the amine products can often be isolated by direct crystallization as hydrochloride salts. The catalyst and silane are commercially available, air stable, and inexpensive, making the procedure accessible for both laboratory and large-scale applications. Copyright
- Reeves, Jonathan T.,Tan, Zhulin,Marsini, Maurice A.,Han, Zhengxu S.,Xu, Yibo,Reeves, Diana C.,Lee, Heewon,Lu, Bruce Z.,Senanayake, Chris H.
-
supporting information
p. 47 - 52
(2013/03/13)
-
- Microwave-assisted synthesis of primary amine HX salts from halides and 7 M ammonia in methanol
-
The atom economical synthesis of hydrogen halide salts of primary amines, directly from the corresponding halides, avoids the production of significant amounts of secondary amine side products, and requires only evaporation of the solvent to access the products in yields generally greater than 90%. The procedure uses microwave irradiation in 7 M ammonia in methanol (Aldrich) at 130°C from 0.5 to 2.5h and works on a variety of alkyl halides, as well as mesylates and tosylates. Benzylamines are obtained from benzyl halides without significant amounts of the secondary amine side products that result without microwave heating. Direct isolation of even highly volatile primary amines as their hydrogen halide salts makes the method ideal for use in parallel synthesis.
- Saulnier, Mark G.,Zimmermann, Kurt,Struzynski, Charles P.,Sang, Xiaopeng,Velaparthi, Upender,Wittman, Mark,Frennesson, David B.
-
p. 397 - 399
(2007/10/03)
-
- Phenethylamines via Heck Arylation of a New Vinylamine Equivalent
-
A new vinylamine equivalent, N-vinyloxazolone 3, has been prepared in three steps and shown to undergo Heck arylation with a variety of substrates.The Heck adducts thus obtained are then converted in one step and high yield to phenethylamine hydrochlorides.As a general synthetic method for preparation of substituted phenethylamines, use of this new reagent is shown to be superior to N-vinylphthalimide in number of steps, regiospecificity, and chemical yield.
- Busacca, Carl A.,Johnson, Robert E.,Swestock, John
-
p. 3299 - 3303
(2007/10/02)
-
- Process for the preparation of β-cyclo-substituted ethylamines
-
The present invention provides a multistep process for the preparation of β-cyclo-substituted ethylamines of the general formula:- in which AR is a heterocyclic or non-heterocyclic aromatic radical, which is optionally mono- or poly- substituted, wherein said compounds represent a class of intermediates which can be converted to 4,5,6,7-tetrahydro[3,2-C] or [2,3-C]pyridines wherein the latter are useful for anti-inflammatory, vasodilator or blood platelet aggregation inhibition activities.
- -
-
-
- Compound 48/80. Structure activity relations and poly THIQ, a new, more potent analog
-
Derivatives of p methoxyphenethylmethylamine were synthesized from which formaldehyde copolymers analogous to compound 48/80 were prepared. Measurement of the hypotensive activity of these analogs revealed that potency was not enhanced by changing the group in the para position, by varying the length of the alkyl group, or by altering the degree of methylation of the amine. However, when the ethylamine side chain was cyclized to form 7 methoxytetrahydroisoquinoline, the copolymer prepared from this derivative (poly THIQ) was seven times more potent than compound 48/80. The hypotensive action of poly THIQ was found to result from the liberation of histamine, as with compound 48/80.
- Read,Kiefer,Weber
-
p. 1292 - 1295
(2007/10/04)
-
