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Jianbo Wang - One of the best experts on this subject based on the ideXlab platform.
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Cu(I)/Chiral Bisoxazoline-Catalyzed Enantioselective Sommelet-Hauser Rearrangement of Sulfonium Ylides.
The Journal of organic chemistry, 2020Co-Authors: Jianbo WangAbstract:Catalytic asymmetric thia-Sommelet–Hauser Rearrangement of sulfonium ylides remains a great challenge due to its multistep reaction mechanism involving metal carbene formation, proton transfer, and...
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catalytic thia sommelet hauser Rearrangement application to the synthesis of oxindoles
Organic Letters, 2011Co-Authors: Yuye Li, Jianbo Wang, Zhongxing Huang, Xinhu Wu, Pengfei Xu, Yan ZhangAbstract:A series of 3-arylthio-1,3-disubstituted-oxindoles were prepared in good yields by the reaction of α-diazocarbonyl compounds and sulfenamides. The reaction involves a Rh-catalyzed thia-Sommelet-Hauser-type Rearrangement.
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Rh(II)-catalyzed Sommelet-Hauser Rearrangement.
Organic letters, 2008Co-Authors: Mingyi Liao, And Lingling Peng, Jianbo WangAbstract:Catalytic Sommelet−Hauser Rearrangement is reported. The Rh(II)-catalyzed reaction of aryldiazoacetates with ethyl benzylthioacetate affords Sommelet−Hauser Rearrangement products in good to excellent yields. This reaction provides a reliable and efficient way to introduce a substituent to the ortho position of arylacetates.
Eiji Tayama - One of the best experts on this subject based on the ideXlab platform.
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Base-induced Sommelet–Hauser Rearrangement of N-(α-(2-oxyethyl)branched)benzylic glycine ester-derived ammonium salts via a chelated intermediate
Tetrahedron, 2020Co-Authors: Eiji Tayama, Kazuki Hirano, Souya BabaAbstract:Abstract The base-induced Sommelet–Hauser (S–H) Rearrangement of N-(α-branched)benzylic glycine ester-derived ammonium salts 1 was investigated. When the α-branched substituent was a simple alkyl, such as a methyl or butyl, desired S–H Rearrangement product 2 was obtained in low yield with formation of the [1,2] Stevens rearranged 4 and Hofmann eliminated products 5 and 6. However, when the α-branched substituent had a 2-oxy moiety, such as 2-acetoxyethyl or 2-benzoyloxyethyl, the yields of 2 were improved. These results could be explained by formation of chelated intermediate C that stabilizes the carbanionic ylide, and the subsequent initial dearomative [2,3] sigmatropic Rearrangement would be accelerated. The existence of C was supported by mechanistic experiments. This enhancement effect is not very strong or effective; however, it will expand the synthetic usefulness of ammonium ylide Rearrangements.
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Structural and mechanistic studies of the base-induced Sommelet–Hauser Rearrangement of N-α-branched benzylic azetidine-2-carboxylic acid-derived ammonium salts
Organic & biomolecular chemistry, 2017Co-Authors: Eiji Tayama, Kazutoshi Watanabe, Sho SotomeAbstract:The base-induced Sommelet–Hauser Rearrangement of N-α-branched benzylic azetidine-2-carboxylic acid ester-derived ammonium salts to obtain α-arylazetidine-2-carboxylic acid esters was investigated. The substrates, two diastereomeric salts (1S,2S,1′S)- and (1R,2R,1′S)-2, showed different reactivities. The Rearrangement of (1S,2S,1′S)-2a proceeded with a perfect N-to-C chirality transfer to provide (R)-3a in 74% yield with 99% ee. However, the Rearrangement of (1R,2R,1′S)-2a under the same conditions afforded (S)-3a in only 15% yield with a lower 66% ee, along with the competitive [1,2] Stevens Rearrangement product 4a. Structural and mechanistic studies of this Rearrangement were carried out to clarify the exact reason. Our results define the scope and limitations of the Sommelet–Hauser Rearrangement and provide unique synthetic access to α-aryl amino acid derivatives.
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Ring‐Strain Effects in Base‐Induced Sommelet–Hauser Rearrangement: Application to Successive Stereocontrolled Transformations
European Journal of Organic Chemistry, 2016Co-Authors: Eiji Tayama, Kazutoshi Watanabe, Yoshihiro MatanoAbstract:The base-induced Sommelet–Hauser (S–H) Rearrangement of azetidine-2-carboxylic acid ester-derived ammonium salts into 2-aryl-substituted derivatives was demonstrated. The ring-strain of four-membered N-heterocycles enables efficient generation of the desired ylide intermediate and enhances the rate of the S–H Rearrangement. The asymmetric version of the Rearrangement was characterized by excellent levels of successive chirality transmissions. The regio- and stereo-controlled nucleophilic ring opening of the Rearrangement products produced quaternary α-aryl amino acid esters with excellent enantiopurities.
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Recent Advances in the Base‐Induced Sommelet–Hauser Rearrangement of Amino Acid Derived Ammonium Ylides
Chemical record (New York N.Y.), 2015Co-Authors: Eiji TayamaAbstract:The Sommelet-Hauser Rearrangement of N-benzylic ammonium ylides generated from ammonium salts is an interesting and useful transformation that enables one to convert a readily accessible C-N bond into a new C-C bond to an aromatic ring. The Rearrangement was discovered by Sommelet in 1937, studied in detail by Hauser, and applied to organic synthesis by Sato until 1999. Further studies have not advanced because several competitive side reactions and structural limitations of the products severely limit the substrate scope and synthetic applications. In this Personal Account, a history of the research in problem solving and recent advances in the base-induced Sommelet-Hauser Rearrangement are described. This synthetic method developed by my group provides efficient access to various types of α-aryl-α-amino acid and α-aryl-β-amino acid derivatives.
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a unique and simple preparative method for α arylpipecolinic acid esters via base induced sommelet hauser Rearrangement
ChemInform, 2013Co-Authors: Eiji Tayama, Ryota Sato, Hajime Iwamoto, Motoshi Ito, Eietsu HasegawaAbstract:Title compounds such as (V) and (IX) are prepared via a new three-step sequence including base-induced Sommelet—Hauser Rearrangement, subsequent von Braun reaction and intramolecular α-alkylation.
Eietsu Hasegawa - One of the best experts on this subject based on the ideXlab platform.
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a unique and simple preparative method for α arylpipecolinic acid esters via base induced sommelet hauser Rearrangement
ChemInform, 2013Co-Authors: Eiji Tayama, Ryota Sato, Hajime Iwamoto, Motoshi Ito, Eietsu HasegawaAbstract:Title compounds such as (V) and (IX) are prepared via a new three-step sequence including base-induced Sommelet—Hauser Rearrangement, subsequent von Braun reaction and intramolecular α-alkylation.
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A Unique and Simple Preparative Method for α-Arylpipecolinic Acid Esters via Base-Induced Sommelet—Hauser Rearrangement.
ChemInform, 2013Co-Authors: Eiji Tayama, Ryota Sato, Hajime Iwamoto, Motoshi Ito, Eietsu HasegawaAbstract:Title compounds such as (V) and (IX) are prepared via a new three-step sequence including base-induced Sommelet—Hauser Rearrangement, subsequent von Braun reaction and intramolecular α-alkylation.
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a formal method for the de n n dialkylation of sommelet hauser Rearrangement products
ChemInform, 2012Co-Authors: Eiji Tayama, Ryota Sato, Keisuke Takedachi, Hajime Iwamoto, Eietsu HasegawaAbstract:The present method furnishes valuable intermediates for preparation of α-aryl-α-amino or α-aryl-β-amino carboxylic acid derivatives.
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A Formal Method for the De-N,N-dialkylation of Sommelet—Hauser Rearrangement Products.
ChemInform, 2012Co-Authors: Eiji Tayama, Ryota Sato, Keisuke Takedachi, Hajime Iwamoto, Eietsu HasegawaAbstract:The present method furnishes valuable intermediates for preparation of α-aryl-α-amino or α-aryl-β-amino carboxylic acid derivatives.
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a formal method for the de n n dialkylation of sommelet hauser Rearrangement products
Tetrahedron, 2012Co-Authors: Eiji Tayama, Ryota Sato, Keisuke Takedachi, Hajime Iwamoto, Eietsu HasegawaAbstract:Abstract Selective amine de-alkylation enables the conversion of Sommelet–Hauser Rearrangement products into 2-aryl-2-bromoacetic acid derivatives. These compounds are valuable synthetic intermediates in the synthesis of α-aryl-α-amino or α-aryl-β-amino acid derivatives. The method presented herein is a formal de-N,N-dialkylation of Sommelet–Hauser Rearrangement products.
Yoshiro Sato - One of the best experts on this subject based on the ideXlab platform.
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Rearrangement of 1-phenyl-3,4-dihydro-1H-2-benzothiopyranium 2-methylides
Journal of the Chemical Society Perkin Transactions 1, 1995Co-Authors: Toru Tanzawa, Yoshiro Sato, Naohiro Shirai, Keiichiro Hatano, Yukihisa KuronoAbstract:trans-1-Phenyl-2-benzothiopyranium 2-methylides (trans-5), generated by fluoride ion-induced desilylation of trans-1-(4-substituted phenyl)-2-(trimethylsilylmethyl)-3,4-dihydro-1H-2-benzothiopyranium triflates (trans-4) in DMSO, rearranged to 3-substituted 7,8-dihydro-5H, 13H-dibenzo[c, f]thionines 6(Sommelet–Hauser Rearrangement products), 1-(4-substituted phenyl)-1,2,4,5-tetrahydro-3-benzothiepines 7(Stevens Rearrangement products) and (4-substituted phenyl)(2-vinylphenyl)methyl methyl sulfides 8(Hofmann degradation products). Reactions carried out in the presence of oxygen, gave (4-substituted phenyl) 2-[2-(methylsulfanyl)ethyl]phenyl ketones 9 as the main products.
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Rearrangement of cis and trans-2-methyl-1-(substituted phenyl)isoindolinium 2-methylides
The Journal of Organic Chemistry, 1994Co-Authors: Akira Sakuragi, Yoshiro Sato, Naohiro Shirai, Yukihisa Kurono, Keiichiro HatanoAbstract:Fluoride ion induced desilylation of cis-2-methyl-1-(sustituted phenyl)-2- [(trimethysilyl)methyl]-isoindolinium iodides cis-5 gave mixtures of the Sommelet-Hauser Rearrangement products 7 and the Stevens products 8 in a ratio about 8.5:1.5. Similar treatments of the trans-isomers (trans-6) afforded exclusively 8. The pathways of the ylide Rearrangement are discussed
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New development of ammonium ylide chemistry
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 1994Co-Authors: Yoshiro Sato, Naohiro ShiraiAbstract:Benzylammonium N-alkylides were generated by reaction of N-[1-(trimethylsilyl)alkyl]benzylammonium salts with cesium fluoride in DMF or HMPA, and their Rearrangement products were investigated. [2,3]Sigmatropic Rearrangement of the ylides initially occurred to give isotoluene derivatives and then they were transformed into Sommelet-Hauser Rearrangement products and/or Stevens products. The isotoluenes having bicyclic structures were stable at room temperature and aromatized with the aid of a base. The relationship between the configuration of cyclic ammonium ylides and the Rearrangement paths is described.
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Sommelet–Hauser or Stevens Rearrangement of 1-methyl-2-(substituted-phenyl)piperazinium 1-methylides. Ring enlargement of piperazines to seven- or nine-membered cyclic amines
J. Chem. Soc. Perkin Trans. 1, 1992Co-Authors: Tomoko Kitano, Naohiro Shirai, Manami Motoi, Yoshiro SatoAbstract:Fluoride ion-induced desilylation of 4-acetyl-1-methyl-2-(4-substituted phenyl)-1-trimethylsilyl-methylpiperazinium iodides 5 gave 5-acetyl-2-methyl-10-substituted 1,3,4,5,6,11a-hexahydro-2H-2,5-benzodiazonines 7 and/or 5-acetyl-2-methyl-10-substituted 2,3,4,5,6,7-hexahydro-1H-2,5-benzodiazonines 8(Sommelet–Hauser Rearrangement products). However, a similar treatment of 1-methyl-3-oxo-2-phenyl-1-trimethylsilylmethylpiperazinium iodide 10 afforded 1-methyl-6-phenyl-2,3,6,7-tetrahydro-1H-diazepine-5-one 12(Stevens Rearrangement product).
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sommelet hauser or stevens Rearrangement of 1 methyl 2 substituted phenyl piperazinium 1 methylides ring enlargement of piperazines to seven or nine membered cyclic amines
Journal of The Chemical Society-perkin Transactions 1, 1992Co-Authors: Tomoko Kitano, Naohiro Shirai, Manami Motoi, Yoshiro SatoAbstract:Fluoride ion-induced desilylation of 4-acetyl-1-methyl-2-(4-substituted phenyl)-1-trimethylsilyl-methylpiperazinium iodides 5 gave 5-acetyl-2-methyl-10-substituted 1,3,4,5,6,11a-hexahydro-2H-2,5-benzodiazonines 7 and/or 5-acetyl-2-methyl-10-substituted 2,3,4,5,6,7-hexahydro-1H-2,5-benzodiazonines 8(Sommelet–Hauser Rearrangement products). However, a similar treatment of 1-methyl-3-oxo-2-phenyl-1-trimethylsilylmethylpiperazinium iodide 10 afforded 1-methyl-6-phenyl-2,3,6,7-tetrahydro-1H-diazepine-5-one 12(Stevens Rearrangement product).
Wang Jianbo - One of the best experts on this subject based on the ideXlab platform.
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Catalytic Thia-Sommelet-Hauser Rearrangement: Application to the Synthesis of Oxindoles
organic letters, 2011Co-Authors: Li Yuye, Wang Jianbo, Yi Shi, Huang Zhongxing, Wu Xinhu, Xu Pengfei, Zhang YanAbstract:A series of 3-arylthio-1,3-disubstituted-oxindoles were prepared in good yields by the reaction of alpha-diazocarbonyl compounds and sulfenamides. The reaction involves a Rh-catalyzed thia-Sommelet-Hauser-type Rearrangement.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000287645800100&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, OrganicSCI(E)PubMed24ARTICLE51210-12131
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Rh(II)-catalyzed Sommelet-Hauser Rearrangement
organic letters, 2008Co-Authors: Liao Mingyi, Peng Lingling, Wang JianboAbstract:Catalytic Sommelet-Hauser Rearrangement is reported. The Rh(II)-catalyzed reaction of aryldiazoacetates with ethyl benzylthioacetate affords Sommelet-Hauser Rearrangement products in good to excellent yields. This reaction provides a reliable and efficient way to introduce a substituent to the ortho position of arylacetates.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000253519600002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, OrganicSCI(E)PubMed14ARTICLE5693-6961