- Metal- and Protection-Free [4 + 2] Cycloadditions of Alkynes with Azadienes: Assembly of Functionalized Quinolines
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A base promoted, protection-free, and regioselective synthesis of highly functionalized quinolines via [4 + 2] cycloaddition of azadienes (generated in situ from o-aminobenzyl alcohol) with internal alkynes has been discovered. The reaction tolerates a wide variety of functional groups which has been successfully extended with diynes, (2-aminopyridin-3-yl)methanol, and 1,4-bis(phenylethynyl)benzene to afford (Z)-phenyl-2-styrylquinolines, phenylnaphthyridine, and alkyne-substituted quinolines, respectively. The proposed mechanism and significant role of the solvent were well supported by isolating the azadiene intermediate and deuterium-labeling studies.
- Saunthwal, Rakesh K.,Patel, Monika,Verma, Akhilesh K.
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supporting information
p. 2200 - 2203
(2016/06/01)
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- Regioselective Synthesis of C-3-Functionalized Quinolines via Hetero-Diels-Alder Cycloaddition of Azadienes with Terminal Alkynes
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A highly efficient metal and protection-free approach for the regioselective synthesis of C-3-functionalized quinolines from azadienes (in situ generated from 2-aminobenzyl alcohol) and terminal alkynes through [4 + 2] cycloaddition has been developed. An unprecedented reaction of 2-aminobenzyl alcohol with 1,3- and 1,4-diethynylbenzene provided the C-3 tolylquinolines via [4 + 2] HDA and oxidative decarboxylation. The -NH2 group directed mechanistic approach was well supported by the control experiments and deuterium-labeling studies and by isolating the azadiene intermediate. The reactivity and selectivity of unprotected azadiene in metal-free base-assisted hetero-Diels-Alder reaction is exploited to quickly assemble an important class of C-3-functionalized quinolines, which are difficult to access.
- Saunthwal, Rakesh K.,Patel, Monika,Verma, Akhilesh K.
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p. 6563 - 6572
(2016/08/16)
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- One-pot catalytic enantioselective synthesis of functionalized tetrahydroquinolines by aza-michael/michael cascade reactions of N-protected 2-aminophenyl α,β-unsaturated esters with Nitroolefins
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A highly enantioselective synthesis of functionalized tetrahydroquinolines with useful biological properties has been developed by means of asymmetric organocatalytic aza-Michael/Michael cascade reactions of nitroolefins with N-protected 2-aminophenyl α,β-unsaturated esters in the presence of a chiral thiourea catalyst. The reaction gave the corresponding highly functionalized tetrahydroquinolines in good yields, excellent diastereoselectivities (>30:1 dr), and high enantioselectivities (≤99% ee).
- Kang, Ki-Tae,Kim, Sung-Gon
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supporting information
p. 3365 - 3373
(2015/01/09)
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- Excited-state intramolecular proton transfer in 2-(2′- arylsulfonamidophenyl)benzimidazole derivatives: The effect of donor and acceptor substituents
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(Chemical Equation Presented) A series of water-soluble 2-(2′-arylsulfonamidophenyl)benzimidazole derivatives containing electron-donating and accepting groups attached to various positions of the fluorophore π-system has been synthesized and characterize
- Henary, Maged M.,Wu, Yonggang,Cody, John,Sumalekshmy,Li, Jing,Mandal, Subrata,Fahrni, Christoph J.
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p. 4784 - 4797
(2008/02/04)
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