- Phosphoric Acid Catalyzed [4 + 1]-Cycloannulation Reaction of ortho-Quinone Methides and Diazoketones: Catalytic, Enantioselective Access toward cis-2,3-Dihydrobenzofurans
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A highly straightforward route to enantiomerically highly enriched cis-2,3-dihydrobenzofurans has been achieved via addition of α-diazocarbonyl compounds to in situ generated o-QMs catalyzed by a chiral Br?nsted acid. This catalytic strategy provides a direct access to 2,3-dihydrobenzofurans in high yields and with up to 91:9 dr and 99:1 er at ambient temperature. Moreover, a unique phenonium-type rearrangement accounts for product formation with an inverted 2,3-substitution pattern.
- Suneja, Arun,Schneider, Christoph
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supporting information
p. 7576 - 7580
(2019/01/03)
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- Tandem Synthesis of α-Diazoketones from 1,3-Diketones
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A highly efficient synthesis of α-diazoketone was achieved by simply stirring the mixture of 1,3-diketone, TsN3, and MeNH2 in EtOH. It was a tandem reaction including a novel primary amine-catalyzed Regitz diazo transfer of 1,3-diket
- Zhang, Jianlan,Chen, Wenwen,Huang, Dayun,Zeng, Xiaobao,Wang, Xinyan,Hu, Yuefei
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p. 9171 - 9174
(2017/09/11)
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- Amination of phenylketene revisit. Substituent effect on reactivity
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The asymmetric stretching frequencies of the ketene group of the m,p-substituted phenylketenes were found to be correlated with σ The substituent effects for the second-order rate constants of phenylketenes with various amines were not correlated linearly
- Badal, Md. Mizanur Rahman,Zhang, Min,Kobayashi, Shinjiro,Mishima, Masaaki
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p. 856 - 863
(2013/08/15)
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- Potential Thyroliberin Affinity Labels. 1. Chloroacetyl-Substituted Phenylalanylpyrrolidines
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Six analogues of thyroliberin (THR) that have a chloroacetyl substituent at the amino terminus have been prepared as potential affinity labels for the TRH receptor.These compounds are N-(chloroacetyl)-L-alanyl-L-phenylalanylpyrrolidine (ClAc-Ala-Phe-Pyrr; 14), N--L-phenylalanyl>pyrrolidine (m-ClAcBz-Phe-Pyrr; 11a), N--L-alanyl-L-phenylalanylpyrrolidine (m-ClAcBz-Ala-Phe-Pyrr; 15a), N--L-phenylalanylpyrrolidine (p-ClAcBz-Phe-Pyrr; 11b), and N--L-alanyl-L-phenylalanylpyrrolidine (p-ClAcBz-Ala-Phe-Pyrr; 15b).Pyroglutamyl-L-phenylalanylpyrrolidine was also synthesized as a model agonist.Weak agonist activity was observed for 11a, 11b, and 15b.These three analogues do not contain the amide group of the pyroglutamyl moiety that was previously thought to be essential for intrinsic activity.No significant antagonist activity was observed for these compounds at the doses tested.
- Goebel, Richard J.,Currie, Bruce L.,Bowers, Cyril Y.
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p. 366 - 370
(2007/10/02)
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