- Reductive one batch synthesis of N-substituted pyrrolidines from primary amines and 2,5-dimethoxytetrahydrofuran
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The construction of the pyrrolidine ring about a nitrogen of a primary amine by a reductive condensation reaction using 2,5- dimethoxytetrahydrofuran and sodium borohydride in acidic water medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electron effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups. The reaction allows the introduction of two deuterium atoms, with label conservation, in both the α-positions of the pyrrolidine ring by the use of sodium borodeuteride instead of sodium borohydride.
- Verardo, Giancarlo,Dolce, Anna,Toniutti, Nicoletta
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- Organic photoredox catalytic α-C(sp3)-H phosphorylation of saturated: Aza -heterocycles
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A metal-free C(sp3)-H phosphorylation of saturated aza-heterocycles via the merger of organic photoredox and Br?nsted acid catalyses was established under mild conditions. This protocol provided straightforward and economic access to a variety of valuable α-phosphoryl cyclic amines by using commercially available diarylphosphine oxide reagents. In addition, the D-A fluorescent molecule DCQ was used for the first time as a photocatalyst and exhibited an excellent photoredox catalytic efficiency in this transformation. A series of mechanistic experiments and DFT calculations demonstrated that this transformation underwent a sequential visible light photoredox catalytic oxidation/nucleophilic addition process.
- Yi, Ming-Jun,Xiao, Teng-Fei,Li, Wen-Hui,Zhang, Yi-Fan,Yan, Pen-Ji,Zhang, Baoxin,Xu, Peng-Fei,Xu, Guo-Qiang
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supporting information
p. 13158 - 13161
(2021/12/16)
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- Phosphoryl chloride-mediated solvent-free synthesis of N-aryl-substituted azacycles from arylamines and cyclic ethers
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A solvent- and metal-free protocol for preparation of N-aryl substituted azacycles from arylamines and cyclic ethers is described. In this method, the combination of POCl3 and DBU is crucial for conversion of arylamines and cyclic ethers to five- and six-membered azacycles. Without solvent, a variety of N-aryl-substituted, five-membered azacycles (pyrrolidines, 2-methylpyrrolidines, and piperidine) and six-membered azacycles (isoindolines and tetrahydroisoquinolines) are synthesized in high yields. This green method provides a sustainable and efficient approach for the preparation of azacycles from various cyclic ethers.
- Tran, Van Hieu,La, Minh Thanh,Kim, Hee-Kwon
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supporting information
p. 1860 - 1863
(2019/06/19)
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- Metal-Free Synthesis of N-Aryl-Substituted Azacycles from Cyclic Ethers Using POCl3
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A facile method for the synthesis of N-aryl-substituted azacycles from arylamines and cyclic ethers has been developed. In this study, arylamines were treated with cyclic ethers in the presence of POCl3 and DBU to provide five- A nd six-membered azacycles. Using this method, various azacycloalkanes, isoindolines, and tetrahydroisoquinolines were prepared in high yields. This synthetic method offers an efficient approach to the production of azacycles from cyclic ethers.
- La, Minh Thanh,Kang, Soosung,Kim, Hee-Kwon
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p. 6689 - 6696
(2019/06/14)
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- Dual C(sp3)?H Bond Functionalization of N-Heterocycles through Sequential Visible-Light Photocatalyzed Dehydrogenation/[2+2] Cycloaddition Reactions
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Herein we describe a mild method for the dual C(sp3)?H bond functionalization of saturated nitrogen-containing heterocycles through a sequential visible-light photocatalyzed dehydrogenation/[2+2] cycloaddition procedure. As a complementary approach to the well-established use of iminium ion and α-amino radical intermediates, the elusive cyclic enamine intermediates were effectively generated by photoredox catalysis under mild conditions and efficiently captured by acetylene esters to form a wide array of bicyclic amino acid derivatives, thus enabling the simultaneous functionalization of two vicinal C(sp3)?H bonds.
- Xu, Guo-Qiang,Xu, Ji-Tao,Feng, Zhi-Tao,Liang, Hui,Wang, Zhu-Yin,Qin, Yong,Xu, Peng-Fei
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supporting information
p. 5110 - 5114
(2018/03/27)
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- A convenient synthesis of hindered N-ARYL substituted cyclic amines
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An efficient and high yielding synthesis of N-substituted pyrrolidines and piperidines is described.
- Akula, Murthy R.,Kabalka, George W.
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p. 2063 - 2070
(2007/10/03)
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- gem-cyclodialkylation A facile synthetic route to N-substituted heterocycles
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N-alkylated and N-arylated pyrroles, pyrrolidines, and piperidines are synthesized in high yield by the reaction between cyclic ethers and primary amines over a heterogeneous titania catalyst.
- Hargis, Duane C.,Shubkin, Ronald L.
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p. 2991 - 2994
(2007/10/02)
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