- Rhodium-catalyzed synthesis of α-amido- and α-carboxylic- β-ketoesters
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The rhodium-catalyzed N-H and O-H insertion of amides and carboxylic acids with α-diazo-β-ketoesters to give different α-amido- and α-carboxylic-β-ketoesters is presented. Investigations were carried out to establish an efficient N-H and O-H insertion reaction using a range of different amides and carboxylic acids for the synthesis of intermediates e.g. for receptor antagonists. The reactions were performed under mild conditions with 1 mol% of catalyst and the products were formed in good yields. Georg Thieme Verlag Stuttgart.
- Bertelsen, Soren,Nielsen, Martin,Bachmann, Stephan,Jorgensen, Karl Anker
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- TBAI-catalyzed oxidative coupling of β-ketoesters with carboxylic acid: Synthesis of α-carboxylic-β-ketoesters
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TBAI-catalyzed oxidative coupling of β-ketoesters with carboxylic acid using TBHP as oxidant has been established. This transformation provides a facile and direct strategy for the synthesis of α-carboxylic-β- ketoesters. ARKAT-USA, Inc.
- Li, Xiaoqing,Zhou, Can,Xu, Xiangsheng
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p. 150 - 158
(2013/01/16)
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- A new approach to the synthesis of 2-aryl-4-halomethyl-5-methyl-1,3- oxazoles by highly regioselective direct halogenation with NBS or NCS/MeCN
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A simple and efficient method for the synthesis of 2-aryl-4-bromomethyl-5- methyl-1,3-oxazoles 2 and 2-aryl-4-chloromethyl-5-methyl-1,3-oxazoles 3 is described. The reaction of 2-aryl-4,5-dimethyl-1,3-oxazoles 1 with N-bromosuccinimide and N-chlorosuccini
- Yamane, Taihei,Mitsudera, Hiroyuki,Shundoh, Takatsugu
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p. 2825 - 2832
(2007/10/03)
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- Highly Enantioselective Reduction of Ethyl 2-Acyloxy-3-oxobutanoate with Immobilized Baker's Yeast
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Reduction of ethyl 2-acetoxy-3-oxobutanoate (4a) with immobilized baker's yeast in calcium alginate gel gave a 18:19:63 mixture of ethyl (2R,3S)- and (2S,3S)-2-acetoxy-3-hydroxybutanoates and ethyl (2S,3S)-2,3-dihydroxybutanoate each with >95percent e.e. in 58percent yield.A similar treatment of a 2-benzoyloxy analog of 4a afforded a 6:94 mixture of ethyl (2R,3S)- and (2S,3S)-2-benzoyloxybutanoates (>95percent e.e.) in 70percent yield.Their absolute configurations were determined by comparison with authentic (2R,3S)- and (2S,3S)-2,3-dihydroxybutanoic acids.Effects of the immobilization and the pH of culture solution on the product ratio are also discussed.
- Sakai, Takashi,Nakamura, Toshiki,Fukuda, Katsuyoshi,Amano, Eiichiro,Utaka, Masanori,Takeda, Akira
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p. 3185 - 3188
(2007/10/02)
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