The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Toshiro Ibuka - One of the best experts on this subject based on the ideXlab platform.
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THE AZA-Payne Rearrangement : A SYNTHETICALLY VALUABLE EQUILIBRATION
Chemical Society Reviews, 1998Co-Authors: Toshiro IbukaAbstract:An aza-Payne Rearrangement of N-activated 2-aziridinemethanols, synthesized in an optically active form, with potassium tert-butoxide (ButOK), potassium hydride (KH), or sodium hydride (NaH) at near 0 °C in common aprotic solvents such as tetrahydrofuran (THF), toluene, or a mixed solvent of THF–HMPA followed by quenching at low temperature gives the corresponding epoxy sulfonamides in high yields. The anionic reaction intermediates, generated by treatment of 2-aziridinemethanols with a base, react readily in a one-pot manner with a variety of nucleophiles such as organocopper reagents, thiols, and trimethylsilyl cyanide to yield the optically active corresponding functionalized 1,2-amino alcohols in good yields. Upon exposure of 2,3-epoxy amines to an equimolar mixture of ButOK and BuLi (super base) in a mixed solvent of THF and n-hexane at –78 °C, the equilibrium lies exclusively toward the hydroxyaziridine forming direction.
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An aza-Payne Rearrangement-epoxide ring opening reaction of 2-aziridinemethanols in a one-pot manner: A regio- and stereoselective synthetic route to diastereomerically pure N-protected 1,2-amino alcohols
Tetrahedron, 1996Co-Authors: Toshiro Ibuka, Hirokazu Tamamura, Nobutaka Fujii, Kazuo Nakai, Masako Akaji, Yoshinori YamamotoAbstract:Abstract A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols via a one-pot aza-Payne Rearrangement - epoxide ring opening reaction of 2-aziridinemethanols is reported.
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A one-pot aza-Payne Rearrangement-epoxide ring opening reaction of 2-aziridinemethanols: A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols
Tetrahedron Letters, 1995Co-Authors: Kazuo Nakai, Toshiro Ibuka, Hirokazu Tamamura, Akira Otaka, Nobutaka Fujii, Yoshinori YamamotoAbstract:Abstract A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols via a one-pot aza-Payne Rearrangement — epoxide ring opening reaction of 2-aziridinemethanols is reported. Satisfactory yields are obtained in excellent diastereoisomeric excesses by successive exposure of 2-aziridinemethanols to potassium hydride and nucleophilic reagents in a one-pot manner.
Babak Borhan - One of the best experts on this subject based on the ideXlab platform.
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Diastereomerically and enantiomerically pure 2,3-disubstituted pyrrolidines from 2,3-aziridin-1-ols using a sulfoxonium ylide: a one-carbon homologative relay ring expansion.
Journal of the American Chemical Society, 2007Co-Authors: Jennifer M. Schomaker, Somnath Bhattacharjee, Jun Yan, Babak BorhanAbstract:An ylide-based aza-Payne Rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne Rearrangement under basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring-closure yields the desired pyrrolidine, thus completing the relay of the three-membered to the five-membered nitrogen-containing ring system. This process takes place with complete transfer of stereochemical fidelity and can be applied to sterically hindered aziridinols.
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Synthesis of diastereomerically and enantiomerically pure 2,3-disubstituted tetrahydrofurans using a sulfoxonium ylide
Journal of the American Chemical Society, 2004Co-Authors: Jennifer M. Schomaker, Veera Reddy Pulgam, Babak BorhanAbstract:Nucleophilic substitution reactions of 2,3-epoxy alcohols, easily prepared via Sharpless asymmetric epoxidation chemistry, offer access to a wide variety of enantiomerically pure compounds. In this communication, we describe the use of a Payne Rearrangement to control regioselectivity in the ring-opening of a series of 2,3-epoxy alcohols with dimethylsulfoxonium methylide to yield diastereomerically and/or enantiomerically pure disubstituted tetrahydrofuran rings. The factors influencing the success and substitution pattern of the THF ring products are discussed, including steric, electronic, and solvent effects.
Yoshinori Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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An aza-Payne Rearrangement-epoxide ring opening reaction of 2-aziridinemethanols in a one-pot manner: A regio- and stereoselective synthetic route to diastereomerically pure N-protected 1,2-amino alcohols
Tetrahedron, 1996Co-Authors: Toshiro Ibuka, Hirokazu Tamamura, Nobutaka Fujii, Kazuo Nakai, Masako Akaji, Yoshinori YamamotoAbstract:Abstract A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols via a one-pot aza-Payne Rearrangement - epoxide ring opening reaction of 2-aziridinemethanols is reported.
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A one-pot aza-Payne Rearrangement-epoxide ring opening reaction of 2-aziridinemethanols: A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols
Tetrahedron Letters, 1995Co-Authors: Kazuo Nakai, Toshiro Ibuka, Hirokazu Tamamura, Akira Otaka, Nobutaka Fujii, Yoshinori YamamotoAbstract:Abstract A regio- and stereoselective synthetic route to diastereomerically pure 1,2-amino alcohols via a one-pot aza-Payne Rearrangement — epoxide ring opening reaction of 2-aziridinemethanols is reported. Satisfactory yields are obtained in excellent diastereoisomeric excesses by successive exposure of 2-aziridinemethanols to potassium hydride and nucleophilic reagents in a one-pot manner.
Dorian P. Nelson - One of the best experts on this subject based on the ideXlab platform.
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Dynamic kinetic resolution during a vinylogous Payne Rearrangement: A concise synthesis of the polar pharmacophoric subunit of (+)-scyphostatin
Organic letters, 2010Co-Authors: Thomas R. Hoye, Christopher S. Jeffrey, Dorian P. NelsonAbstract:The diastereomeric epoxycyclohexenols 3a/b (obtained via a Wharton Rearrangement of a bis-epoxycyclohexanone precursor) were shown to undergo interconversion via a facile vinylogous Payne Rearrangement. Mechanistic issues were probed; the doubly O-deuterated analogues underwent this equilibration more slowly than the parent dihydroxy compounds. It was possible to kinetically resolve the mixture of 3a/b under equilibrating conditions by use of Amano PS. This DKR is additionally noteworthy because it sets four stereocenters in a single event.
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dynamic kinetic resolution during a vinylogous Payne Rearrangement a concise synthesis of the polar pharmacophoric subunit of scyphostatin
Organic Letters, 2010Co-Authors: Thomas R. Hoye, Christopher S. Jeffrey, Dorian P. NelsonAbstract:The diastereomeric epoxycyclohexenols 3a/b (obtained via a Wharton Rearrangement of a bis-epoxycyclohexanone precursor) were shown to undergo interconversion via a facile vinylogous Payne Rearrangement. Mechanistic issues were probed; the doubly O-deuterated analogues underwent this equilibration more slowly than the parent dihydroxy compounds. It was possible to kinetically resolve the mixture of 3a/b under equilibrating conditions by use of Amano PS. This DKR is additionally noteworthy because it sets four stereocenters in a single event.
Srinivasan Chandrasekaran - One of the best experts on this subject based on the ideXlab platform.
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Tetrathiomolybdate mediated Rearrangement of aziridinemethanol tosylates: a thia-aza-Payne Rearrangement.
The Journal of organic chemistry, 2010Co-Authors: Devarajulu Sureshkumar, Srinivasamurthy Koutha, Venkataraman Ganesh, Srinivasan ChandrasekaranAbstract:Aziridinemethanol sulfonate esters react with tetrathiomolybdate 1 to give thiirane derivatives as the major product and cyclic disulfides as minor product under mild reaction conditions via an unprecedented thia-aza-Payne-type Rearrangement. Interestingly, when the reaction of 1 was carried out with 2-aziridino-cyclohexanol derivatives it resulted in the formation of thia-bicyclo[3.1.1]heptane or dithia-bicyclo[3.2.1]octane derivatives.