220445-67-0Relevant academic research and scientific papers
Rhodium-catalyzed oxidative amidation of allylic alcohols and aldehydes: Effective conversion of amines and anilines into amides
Wu, Zhao,Hull, Kami L.
, p. 969 - 975 (2016/02/05)
The rhodium-catalyzed oxidative amidation of allylic alcohols and aldehydes is reported. In situ generated [(BINAP)Rh]BF4 catalyzes the one-pot isomerization/oxidative amidation of allylic alcohols or direct amidation of aldehydes using acetone or styrene as the hydrogen acceptor. The conditions are general, affording good to excellent yields with a wide array of amine and aniline nucleophiles, and chemoselective, other alcohols do not participate in the oxidation reaction. Utilization of biphasic conditions is critical, as they promote an equilibrium between the imine/enamine byproducts and the hemiaminal, which can undergo oxidation to the amide.
The ruthenium-catalyzed reduction and reductive N-alkylation of secondary amides with hydrosilanes: Practical synthesis of secondary and tertiary amines by judicious choice of hydrosilanes
Hanada, Shiori,Ishida, Toshiki,Motoyama, Yukihiro,Nagashima, Hideo
, p. 7551 - 7559 (2008/02/12)
(Chemical Equation Presented) A triruthenium cluster, (μ3, η2,η3,η5-acenaphthylene)Ru 3(CO)7 (1) catalyzes the reaction of secondary amides with hydrosilanes, yielding a mixture of secondary amines, tertiary amines, and silyl enamines. Production of secondary amines with complete selectivity is achieved by the use of higher concentration of the catalyst (3 mol %) and the use of bifunctional hydrosilanes such as 1,1,3,3-tetramethyldisiloxane. Acidic workup of the reaction mixture affords the corresponding ammonium salts, which can be treated with a base, providing a facile method for isolation of secondary amines with high purity. In contrast, tertiary amines are formed with high selectivity by using lower concentration of the catalyst (1 mol %) and polymeric hydrosiloxanes (PMHS) as reducing agent. Reduction with PMHS encapsulates the ruthenium catalyst and organic byproducts to the insoluble silicone resin. The two reaction manifolds are applicable to various secondary amides and are practical in that the procedures provide the desired secondary or tertiary amine as a single product. The product contaminated with only minimal amounts of ruthenium and silicon residues. On the basis of the products and observed side products as well as NMR studies a mechanistic scenario for the reaction is also described.
Generation and trapping of N-acyliminium ions derived from isomunchnone cycloadducts. A versatile route to functionalized heterocycles
Brodney, Michael A.,Padwa, Albert
, p. 556 - 565 (2007/10/03)
A series of 2-diazo-N-hept-6-enoylmalonamides were prepared and treated with a catalytic amount of rhodium(II) perfluorobutyrate. The resultant carbenoids underwent facile cyclization onto the neighboring amide carbonyl oxygen atom to generate isomunchnone-type intermediates. Subsequent 1,3- dipolar cycloaddition across the pendant olefin afforded intramolecular cycloadducts in high yield. The cascade sequence is simple, direct, and extremely tolerant of structural diversity. Exposure of these cycloadducts to Lewis acids resulted in oxabicyclic ring opening. N-Acyliminium ions of wide structural variety can be easily generated by this sequence of reactions. Different cyclization pathways become available depending on the nature of the substituent group attached to the amide nitrogen. When the tethered group is electrophilic in nature, proton loss from the initially formed N- acyliminium ion occurs rapidly to give an acyl enamide which undergoes a subsequent cyclization at the electrophilic center.
