56037-75-3

Upstream product

• 108-91-8 cyclohexylamine 
• 100-49-2 cyclohexylmethyl alcohol 
• 766-05-2 cyclohexane carbonitrile 
• 7474-36-4 N-cyclohexylcyclohexanecarboxamide 
• 2043-61-0 cyclohexanecarbaldehyde 

Downstream Products

• 536-57-2 p-toluene sulfinic acid 
• 80964-44-9 1,5-dicyclohexyl imidazole 
• 87364-66-7 N-(Cyclohexylmethyl)-N-cyclohexylamine 

Relevant academic research and scientific papers

H2 Activation by Non-Transition-Metal Systems: Hydrogenation of Aldimines and Ketimines with LiN(SiMe3)2

In recent years, H2 activation at non-transition-metal centers has met with increasing attention. Here, a system in which H2 is activated and transferred to aldimines and ketimines using substoichiometric amounts of lithium bis(trimethylsilyl)amide is reported. Notably, the reaction tolerates the presence of acidic protons in the α-position. Mechanistic investigations indicated that the reaction proceeds via a lithium hydride intermediate as the actual reductant.

A BEt3-Base catalyst for amide reduction with silane

Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.

Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines

The preparation of new osmium hydride complexes, starting from OsH6(PiPr3)2 (1) and OsH2Cl2(PiPr3)2 (2), and their catalytic activity in acceptorless dehydrogenative coupling of alcohols and amines and in dehydrogenation of cyclic amines are reported. Complex 1 reacts with acetylacetone (Hacac) to give the classical trihydride OsH3(acac)(PiPr3)2 (3). The protonation of 3 with triflic acid (HOTf) produces the release of H2 and the formation of the unsaturated osmium(IV) dihydride [OsH2(acac)(PiPr3)2]OTf (4), which is also prepared by starting from 2 via the intermediate OsH2Cl(acac)(PiPr3)2 (5). Treatment of an acetylacetone solution of 5 with KOH affords Os(acac)2(PiPr3)2 (6). In the presence of 5 mol % of KOH, complexes 3-6 promote the coupling of benzyl alcohol and aniline to give N-benzylideneaniline and H2. Under the same conditions, complex 3 catalyzes a wide range of analogous couplings to afford a variety of imines, including aliphatic imines, with yields between 90 and 40% after 1-48 h. Complex 3 also catalyzes the dehydrogenation of cyclic amines. According to the amount of H2 released by each 1 g of employed substrate, the amines have been classified into three classes: poor (1,2,3,4-tetrahydroquinaldine, 2-methylindoline, and 2,6-dimethylpiperidine), moderate (1,2,3,4-tetrahydroquinoline and 6-methyl-1,2,3,4-tetrahydroquinoline), and good hydrogen donors (1,2,3,4-tetrahydroisoquinoline).

Iron-Catalyzed Mild and Selective Hydrogenative Cross-Coupling of Nitriles and Amines To Form Secondary Aldimines

The first example of a base-metal-catalyzed homogeneous hydrogenative coupling of nitriles and amines to selectively form secondary cross-imines is reported. The reaction is catalyzed under mild conditions by a well-defined (iPr-PNP)Fe(H)Br(CO) pincer pre-catalyst and catalytic tBuOK.

Aminomethylation reaction of Ortho -pyridyl C-H bonds catalyzed by group 3 metal triamido complexes

Tris[N,N-bis(trimethylsilyl)amido] complexes of group 3 metals, especially yttrium and gadolinium, served as catalysts for ortho-C-H bond addition of pyridine derivatives and N-heteroaromatics into the C=N double bond of nonactivated imines to afford the corresponding aminomethylated products. Addition of catalytic amounts of secondary amines, such as dibenzylamine, dramatically improved the catalytic activity through the formation of a mixed ligated complex such as [(Me3Si)2N]2Y(NBn2)(THF) (4). Furthermore, kinetic studies using the isolated complex 4 provided a plausible reaction mechanism by which coordination of two pyridine derivatives afforded a penta-coordinated species as a key step.

Palladium-catalyzed [4 + 2] cycloaddition of aldimines and 1,4-dipolar equivalents via amphiphilic allylation

The combination of Pd catalyst and diethylzinc with triethylborane promotes the amphiphilic allylation of aldimines with 2,3-bismethylenebutane-1,4-diol derivatives to serve as bis-allylic zwitterion species to form 3,4-bismethylenepiperidines via a formal [4 + 2] cycloaddition reaction. 3,4-Bismethylenepiperidine rings are applicable for the synthesis of isoquinoline derivatives via the Diels-Alder reaction followed by an oxidation reaction with DDQ.

Direct access to pop-type osmium(II) and osmium(IV) complexes: Osmium a promising alternative to ruthenium for the synthesis of imines from alcohols and amines

An easy and direct access to POP-type osmium(II) and osmium(IV) complexes, including OsH4{dbf(PiPr2)2} (dbf(PiPr2)2 = 4,6-bis(diisopropylphosphine) dibenzofuran), is reported. This tetrahydride derivative is an efficient catalyst for the selective formation of imines from alcohols and amines with liberation of H2, proving that osmium is a promising alternative to ruthenium for catalysis.

Anthracene Heme Cyclophanes. Steric Effects in CO, O2, and RNC Binding

Equilibrium constants in benzene solution are reported for binding of imidazoles, CO, O2, and isocyanide to two anthracene heme cyclophanes, Fe(6,6-cyclophane) and Fe(7,7-cyclophane), containing a conformationally mobile anthracene ring strapped symmetrically over the heme.The Fe(6,6-cyclophane) shows an approximately 300-fold reduction in affinity for the diatomic molecules, CO, and O2 compared to unhindered hemes.The Fe(7,7-cyclophane) shows only slight steric effects toward CO and O2 but larger effects with bulky isocyanides.The sizes of the cyclophane cavities are qualitatively probed with isocyanides of varying size.Kinetic data for binding of CO, O2, and tosylmethyl isocyanide to heme cyclophanes when compared to similar data for flat analogues demonstrate that steric effects are manifested primarily in the ligand association rates.This feature of the cyclophane is very similar to observed steric effects in hemoproteins, suggesting that large conformational changes (tilting of the cyclophane cap in the models and movement of distal protein residues in hemoproteins) occur in both prior to the transition state for ligation.Magnitudes of steric effects in hemoproteins and cyclophanes are calculated on the basis of comparison with the unhindered chelated heme model compounds.The nature of the distal steric effect in the Fe(6,6-cyclophane) model compound suggests that the reported bending or tilting of CO in hemoglobins and myoglobin may be of minor chemical significance.