- Kinetic Resolution of Racemic Allylic Alcohols by Catalytic Asymmetric Substitution of the OH Group with Monosubstituted Hydrazines
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A new strategy has been established for the kinetic resolution of racemic allylic alcohols through a palladium/sulfonyl-hydrazide-catalyzed asymmetric OH-substitution under mild conditions. In the presence of 1 mol % [Pd(allyl)Cl]2, 4 mol % (S)-SegPhos, and 10 mol % 2,5-dichlorobenzenesulfonyl hydrazide, a range of racemic allylic alcohols were smoothly resolved with selectivity factors of more than 400 through an asymmetric allylic alkylation of monosubstituted hydrazines under air at room temperature. Importantly, this kinetic resolution process provided various allylic alcohols and allylic hydrazine derivatives with high enantiopurity.
- Yan, Liang,Xu, Jing-Kun,Huang, Chao-Fan,He, Zeng-Yang,Xu, Ya-Nan,Tian, Shi-Kai
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supporting information
p. 13041 - 13045
(2016/09/09)
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- Carbonylative Mizoroki-Heck Reaction of Alkyl Iodides with Arylalkenes Using a Pd/Photoirradiation System
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A carbonylative Mizoroki-Heck reaction using alkyl iodides was achieved with a Pd/photoirradiation system using DBU as a base. In this reaction, alkyl radicals were formed from alkyl iodides via single-electron transfer (SET) and then underwent a sequential addition to CO and alkenes to give β-keto radicals. It is proposed that DBU would abstract a proton α to carbonyl to form radical anions, giving α,β-unsaturated ketones via SET.
- Sumino, Shuhei,Ui, Takahito,Hamada, Yuki,Fukuyama, Takahide,Ryu, Ilhyong
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supporting information
p. 4952 - 4955
(2015/11/03)
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- Palladium-catalyzed coupling reaction of acylzirconocene chlorides with hypervalent iodonium salts: Synthesis of aryl-substituted ketones
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The palladium-catalyzed acylation reaction of alkenoyl- and alkanoylzirconocene chlorides with hypervalent iodonium salts afforded the acylated aromatic compounds under mild conditions.
- Kang, Suk-Ku,Yoon, Seok-Keun
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p. 459 - 461
(2007/10/03)
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- Triphenylphosphine-mediated olefination of aldehydes with (Z)-(2- acetoxyalk-1-enyl)phenyl-λ3-iodanes: Generation and reaction of (2- oxoalkyl)phenyl-λ3-iodanes
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(Z)-(2-Acetoxyalk-1-enyl)phenyl-λ3-iodanes, on treatment with triethylamine in methanol in the presence of triphenylphosphine, undergo Wittig olefination with aldehydes, which involves the intermediacy of α- iodanyl ketones generated by in situ
- Ochiai, Masahito,Nishi, Yoshio,Nishitani, Junichi,Chen, Da-Wei,Hashimoto, Sakiko,Tsuchimoto, Yoshimi
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p. 1157 - 1158
(2007/10/03)
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- Benzotriazole- and 1,2,4-triazole-stabilized allylic anions: Applications in syntheses of functionalized α,β-unsaturated ketones, γ-lactones, γ-lactams, and β-substituted esters
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Deprotonated 1-(benzotriazol-1-yl)-1-ethoxy-2-hexene (7) reacted with alkyl halides, aldehydes, ketones, imines, and α,β-unsaturated esters to give exclusively the α-alkylated products 8a-c, 10a,b, 12, 14, 16, and 18a,b, respectively. Without isolation, these products were hydrolyzed under mild conditions to generate the corresponding simple or functionalized α,β-unsaturated ketenes 9a-c, 11a,b, 13, 15, 17, and 19a,b. Similar reactions with the phenyl-substituted analog 3-(benzotriazol-1-yl)-3-ethoxy-1-phenyl-1-propene (21) also gave the analogous α-products, but they were accompanied by small amounts of the γ-products in most cases. By contrast, deprotonation of the corresponding triazole derivative 29 with butyllithium followed by reactions with alkyl halides, aldehydes, ketones, or imines yielded exclusively γ-alkylated adducts 32, 34, 36, 38, 40, and 42. Intermediates 32, 34, 36, 38, 40, and 42 were readily converted into β-substituted esters 33a-c, γ-lactones 35a,b, 39, 41, and 43, and γ-lactams 37a-c on hydrolysis.
- Katritzky,Feng,Lang
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p. 706 - 714
(2007/10/03)
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