189161-99-7Relevant academic research and scientific papers
Dehydrogenation and α-functionalization of secondary amines by visible-light-mediated catalysis
Bujok, Robert,Morawska, Paulina,Pawlowski, Robert,Stanek, Filip,Stodulski, Maciej
supporting information, p. 2103 - 2112 (2020/03/27)
A visible-light-mediated process for dehydrogenation of amines has been described. The given protocol showed a broad substrate scope, mild reaction conditions and excellent results without the requirement of tedious purification. This process can be applied in one-pot functionalization of secondary amines with various nucleophiles through the cooperation of visible-light and Lewis acid catalysis, leading to the structurally varied essential components of biologically active molecules. In addition, Stern-Volmer studies and quenching experiments revealed the role of a catalyst and led to the proposed mechanism of this transformation.
Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines
Esteruelas, Miguel A.,Lezáun, Virginia,Martínez, Antonio,Oliván, Montserrat,Onate, Enrique
, p. 2996 - 3004 (2017/08/21)
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).
Asymmetric Petasis Borono-Mannich Allylation Reactions Catalyzed by Chiral Biphenols
Jiang, Yao,Schaus, Scott E.
supporting information, p. 1544 - 1548 (2017/02/05)
Chiral biphenols catalyze the asymmetric Petasis borono-Mannich allylation of aldehydes and amines through the use of a bench-stable allyldioxaborolane. The reaction proceeds via a two-step, one-pot process and requires 2–8 mole % of 3,3′-Ph2-BINOL as the optimal catalyst. Under microwave heating the reaction affords chiral homoallylic amines in excellent yields (up to 99 %) and high enantioselectivies (er up to 99:1). The catalytic reaction is a true multicomponent condensation reaction whereas both the aldehyde and the amine can possess a wide range of structural and electronic properties. Use of crotyldioxaborolane in the reaction results in stereodivergent products with anti- and syn-diastereomers both in good diastereoselectivities and enantioselectivities from the corresponding E- and Z-borolane stereoisomers.
Au/Ag-Mo nano-rods catalyzed reductive coupling of nitrobenzenes and alcohols using glycerol as the hydrogen source
Cui, Xinjiang,Zhang, Chengming,Shi, Feng,Deng, Youquan
supporting information; experimental part, p. 9391 - 9393 (2012/09/21)
A highly efficient Au/Ag-Mo nano-rods catalyst was prepared for the one-pot synthesis of imine and amine using equal molar ratio of nitrobenzene and alcohol as starting materials, and bio-based glycerol as the hydrogen source. The reaction mechanism of the nitrobenzene reduction, amine and aldehyde coupling, and imine reduction was explored.
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
Esteruelas, Miguel A.,Honczek, Nicole,Olivan, Montserrat,Onate, Enrique,Valencia, Marta
scheme or table, p. 2468 - 2471 (2011/06/27)
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.
