An improved protocol for the selective hydroaminomethylation of arylethylenes

A practical and benign synthesis of primary amines through ruthenium-catalyzed reduction of nitriles

The catalytic hydrogenation of nitriles represents an atom-economic and valuable route to amines. In the present study, the ruthenium-catalyzed hydrogenation of various organic nitriles to give primary amines has been examined in detail. Straightforward ruthenium complexes modified by cheap and widely available triphenylphosphine allow for the efficient and general reduction of various aryl, alkyl, and heterocyclic nitriles. By using a practical in situ catalyst composed of [Ru(cod)(methylallyl(2))] and PPh(3), excellent yields and chemoselectivity were achieved. Moreover, the catalyst system displays broad functional group tolerance.

An Improved Ruthenium Catalyst for the Environmentally Benign Amination of Primary and Secondary Alcohols

The N-alkylation of amines in the presence of different ruthenium catalysts generated in situ was investigated. Among the various catalysts tested, the combination of [Ru3(CO)12] and N-phenyl-2-(dicyclohexylphosphanyl)pyrrole showed the best performance. By applying this novel catalyst, a variety of functionalized alcohols and amines were converted into the corresponding secondary amines in high yield.

Hydroaminomethylation with Novel Rhodium–Carbene complexes: An Efficient Catalytic Approach to Pharmaceuticals

Starting from [{Rh(cod)Cl}(2)] and 1,3-dimesitylimidazole-2-ylidenes the novel [RhCl(cod)(carbene)] complexes 1-5 have been synthesized, characterized, and tested in the hydroaminomethylation of aromatic olefins. The influence of different ligands and reaction parameters on the catalytic activity was investigated in detail applying 1,1-diphenylethylene and piperidine as a model system. The scope and limitations of the novel catalysts is shown in the preparation of 16 biologically active 1-amino-3,3-diarylpropenes. In general, high chemo- and regioselectivity as well as good yields of the desired products were achieved.

Rhodium(i)-catalyzed hydroaminomethylation of 2-isopropenylanilines as a novel route to 1,2,3,4-tetrahydroquinolines

A new atom economical approach for the preparation of 1,2,3,4-tetrahydroquinolines can be achieved by means of the intramolecular hydroaminomethylation of 2-isopropenylanilines, mediated by an ionic diamino rhodium catalyst that does not require phosphine--this reaction is highly chemo- and regioselective, and it occurs in good isolated yields.

Highly Selective Hydroaminomethylation of Internal Alkenes To Give Linear Amines

The application of phenoxaphosphino-modified Xantphos-type ligands (1-9) in the rhodium-catalyzed hydroaminomethylation of internal olefins to give linear amines is reported. Excellent chemo- and regioselectivities have been obtained through the use of 0.1 mol % [Rh(cod)2]BF(4)/0.4 mol % xantphenoxaphos (1), providing a practical and environmentally attractive synthetic route for the preparation of amines from internal alkenes. For the first time, both functionalized internal olefins and mixtures of internal and terminal olefins have been converted highly selectively into linear amines. Investigations of the effects of the calculated natural bite angles of ligands on hydroaminomethylation shows that the regioselectivity for the linear product follows a similar trend to that seen in the hydroformylation of internal alkenes with the aid of these ligands. Hydroaminomethylation and each of its individual steps were monitored by high-pressure infrared spectroscopy. The results suggest that hydroaminomethylations take place by a sequential isomerization/hydroformylation/amination/hydrogenation pathway.