- A direct route to medium and large cyclic amines from aminoalkenes
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Rhodium-catalysed reactions of aminoalkenes with H2/CO give cyclic amines with a range of medium and large ring sizes in yields up to 85%. High regioselectivity for non-branched products can be obtained when BIPHEPHOS is used as a ligand in the
- Bergmann, David J.,Campi, Eva M.,Jackson, W. Roy,Patti, Antonio F.,Saylik, Dilek
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- Atomic Pt-Catalyzed Heterogeneous Anti-Markovnikov C-N Formation: Pt10Activating N-H for Pt1δ+-Activated C-C Attack
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C-N formation is of great significance to synthetic chemistry, as N-containing products are widely used in chemistry, medicine, and biology. Addition of an amine to an unsaturated carbon-carbon bond is a simple yet effective route to produce new C-N bonds. But how to effectively conduct an anti-Markovnikov addition with high selectivity has been a great challenge. Here, we proposed a strategy for highly regioselective C-N addition via hydroamination by using supported Pt. It has been identified that atomic-scale Pt is the active site for C-N addition with Pt12+ for Markovnikov C-N formation and atomic Pt (Pt1δ+ and Pt10) contributing to anti-Markovnikov C-N formation. A selectivity of up to 92% to the anti-Markovnikov product has been achieved with atomic Pt in the addition of styrene and pyrrolidine. A cooperating catalysis for the anti-Markovnikov C-N formation between Pt1δ+ and Pt10 has been revealed. The reaction mechanism has been studied by EPR spectra and in situ FT-IR spectra of adsorption/desorption of styrene and/or pyrrolidine. It has been demonstrated that Pt10 activates amine to be electrophilic, while Pt1δ+ activates C-C by π-bonding to make β-C nucleophilic. The attack of nucleophilic β-C to electrophilic amine affords the anti-Markovnikov addition. This strategy proves highly effective to a variety of substrates in anti-Markovnikov C-N formation, including aromatic/aliphatic amines reacting with aromatic olefins, aromatic/aliphatic olefins with aromatic amines, and linear aliphatic olefins with secondary aliphatic amines. It is believed that the results provide evidence for the function of varied chemical states in monatomic catalysis.
- Ma, Xiaodan,An, Zhe,Song, Hongyan,Shu, Xin,Xiang, Xu,He, Jing
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p. 9017 - 9027
(2020/12/23)
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- Metal Acetylide Elimination: The Key Step in the Cascade Decomposition and Transformation of Metalated Propargylamines
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Metal acetylide elimination facilitates a novel one-pot cascade metalation and elimination/addition route to a series of unsymmetrical secondary amines from the reaction of secondary propargylamines with organometallic reagents. Spectroscopic evidence suggests a dimetalated amido intermediate rather than an allene.
- Flynn, Matthew T.,Blair, Victoria L.,Andrews, Philip C.
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supporting information
p. 1225 - 1228
(2018/04/30)
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- Synthesis of medium and large cyclic amines in rhodium-catalysed reactions of aminoalkenes with H2/CO1
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Rhodium-catalysed reactions of N-benzyl- or N-alkyl-aminoalkenes (6) with H2/CO can give cyclic amines (7) (7-13 ring size) in good to excellent yields when BIPHEPHOS is used as a ligand. Hydrogenation of the aminoalkene becomes a competing reaction for the smaller rings but can be overcome by using a H2/CO gas ratio of 1:5. Reactions of 2-alkenyloxybenzylamines (13) gave 9-, 12- and 17-membered rings (14) in 30-40% yield, but dimer formation (16) and/or hydrogenation were competing reactions. Similar reactions of alkenylamides and ortho-alkenylanilines gave only non-cyclized amino aldehydes as products in low isolated yields.
- Bergmann, David J.,Campi, Eva M.,Roy Jackson,Patti, Antonio F.,Saylik, Dilek
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p. 835 - 844
(2007/10/03)
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