- Silver-catalyzed asymmetric amination of silyl enol ethers
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Catalytic amination of silyl enol ethers with azo diester compounds was investigated. It was shown that Cu(OTf)2 or AgOTf had high catalytic activity and that AgOTf was the most efficient among the catalysts tested in the reactions. In asymmetr
- Yamashita,Ishitani,Kobayashi
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- Frustrated Lewis acid/Br?nsted base catalysts for direct enantioselective α-amination of carbonyl compounds
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A method for enantioselective direct α-amination reaction catalyzed by a sterically "frustrated" Lewis acid/Br?nsted base complex is disclosed. Cooperative functioning of the Lewis acid and Br?nsted base components gives rise to in situ enolate generation from monocarbonyl compounds. Subsequent reaction with hydrogen-bond activated dialkyl azodicarboxylates delivers α-aminocarbonyl compounds in high enantiomeric purity.
- Shang, Ming,Wang, Xiaoxu,Koo, Seung Moh,Youn, Jennifer,Chan, Jessica Z.,Yao, Wenzhi,Hastings, Brian T.,Wasa, Masayuki
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supporting information
p. 95 - 98
(2017/05/16)
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- Synthesis of Amines and Amino Alcohols by Electrophilic Amination and Highly Stereoselective Reduction
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A practical and selective method for the synthesis of the β-arylamines 5 and the cis- or trans-amino alcohols 8 and 11 is reported.The reaction sequence starts from α-tetralones 1 which readily react with dibenzyl azodicarboxylate to afford the protected α-hydrazino ketones 2.Then, depending on the reduction conditions, the trans-hydrazino alcohols 10 or the cis isomers 7 are formed predominantly.The stereoselectivities which range between 18:1 and 1:67 (trans/cis) are explained by stereoelectronic effects (?,?* interactions) and steric hindrance.Depending on the workup procedure, we can control, whether the cis-hydrazino alcohols 7 or the oxazolidinone derivatives 3 are isolated.Subsequent hydrogenolyses of 4, 7 and 10 lead to the target molecules 5, 8 and 11, respectively. Key Words: Electrophilic amination / Dibenzyl azodicarboxylate / Stereoselective reduction
- Gmeiner, Peter,Bollinger, Bernd
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p. 273 - 278
(2007/10/02)
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- Efficient Methodology for the Preparation of β-Aminotetralin Derivatives via Electrophilic Amination
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A mild and efficient method for the construction of β-aryl amines from the corresponding α-aryl ketones is presented.The key step of the synthesis involve an electrophilic amination by dibenzyl azodicarboxylate followed by a stereoselective LiHBEt3 reduction.The reaction sequence is applied to the synthesis of the tricyclic ergoline analogue 4. Key words: electrophilic amination; stereoselective reduction; α-amino ketones.
- Gmeiner, Peter,Bollinger, Bernd
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p. 5927 - 5930
(2007/10/02)
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