- Organocatalytic Enantioselective Addition of α-Aminoalkyl Radicals to Isoquinolines
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With a dual organocatalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and under the irradiation with visible light, an enantioselective Minisci-type addition of α-amino acid-derived redox-active esters (RAEs) to isoquinolines has been developed. A variety of prochiral α-aminoalkyl radicals generated from RAEs were successfully introduced on isoquinolines, providing a range of valuable α-isoquinoline-substituted chiral secondary amines in high yields with good to excellent enantioselectivities.
- Liu, Xiangyuan,Liu, Yang,Chai, Guobi,Qiao, Baokun,Zhao, Xiaowei,Jiang, Zhiyong
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supporting information
p. 6298 - 6301
(2018/10/09)
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- Use of acetate as a leaving group in palladium-catalyzed nucleophilic substitution of benzylic esters
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The palladium complex prepared in situ from [Pd(η3-C3H5)(cod)]BF4 and bidentate phosphine DPPF was a good catalyst for the nucleophilic substitution of benzyl acetate. Significant acceleration of the palladium-catalyzed substitution was observed when an alcohol was employed as a reaction solvent. The palladium catalyst was effective for the benzylation of various stabilized carbanions, amines, and benzenesulfinate with benzylic acetates.
- Yokogi, Masashi,Kuwano, Ryoichi
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p. 6109 - 6112
(2008/03/12)
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- Synthetic and biotransformation studies on prochiral non-proteinogenic amino acids: Diethyl α-acetamido, α-alkylmalonates
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Nine diethyl α-acetamido, α-alkylmalonates 3-11 (alkyl=methyl, benzyl, 3-fluorobenzyl, 4-fluorobenzyl, 2,6-difluorobenzyl, 3-trifluoromethylbenzyl, 4-trifluoromethylbenzyi, 2-chlorobenzyl and 3-chlorobenzyl) have been synthesised in three steps starting with diethyl malonate in overall yields of 49-90%. The structures of C-alkylated acetamidomalonates have been established on the basis of their speciral data, the structures of two compounds 9 and 11 are also confirmed on the basis of their X-ray crystallographic studies. Further, the X-ray crystal structure of the chiral monoethyl ester of α-acetamidomalonic acid 1 has been studied. None of our C-alkylated acetamidomalonate has been found to be a substrate for lipase-catalysed enantiodifferentiating deesterification/hydrolysis of the symmetric diester groups.
- Singh,Prasad,Errington,Belokon,Kochetkov,Saxena,Jain,Parmar
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