- Asymmetric Enzymatic Synthesis of Allylic Amines: A Sigmatropic Rearrangement Strategy
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Sigmatropic rearrangements, while rare in biology, offer opportunities for the efficient and selective synthesis of complex chemical motifs. A "P411" serine-ligated variant of cytochrome P450BM3 has been engineered to initiate a sulfimidation/[2,3]-sigmatropic rearrangement sequence in whole E. coli cells, a non-natural function for any enzyme, providing access to enantioenriched, protected allylic amines. Five mutations in the enzyme substantially enhance its activity toward this new function, demonstrating the evolvability of the catalyst toward challenging nitrene transfer reactions. The evolved catalyst additionally performs the highly enantioselective imidation of non-allylic sulfides.
- Prier, Christopher K.,Hyster, Todd K.,Farwell, Christopher C.,Huang, Audrey,Arnold, Frances H.
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supporting information
p. 4711 - 4715
(2016/04/19)
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- Fluorinated alcohols as promoters for the metal-free direct substitution reaction of allylic alcohols with nitrogenated, silylated, and carbon nucleophiles
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The direct allylic substitution reaction using allylic alcohols in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and 2,2,2-trifluoroethanol (TFE) as reaction media is described. The developed procedure is simple, works under mild conditions (rt, 50 and 70 °C), and proves to be very general, since different nitrogenated nucleophiles and carbon nucleophiles can be used achieving high yields, especially when HFIP is employed as solvent and aromatic allylic alcohols are the substrates. Thus, sulfonamides, carbamates, carboxamides, and amines can be successfully employed as nitrogen-based nucleophiles. Likewise, silylated nucleophiles such as trimethylsilylazide, allyltrimethylsilane, trimethylsilane, and trimethylsilylphenylacetylene give the corresponding allylic substitution products in high yields. Good results for the Friedel-Crafts adducts are also achieved with aromatic compounds (phenol, anisole, indole, and anilines) as nucleophiles. Particularly interesting are the results obtained with electron-rich anilines, which can behave as nitrogenated or carbon nucleophiles depending on their electronic properties and the solvent employed. In addition, 1,3-dicarbonyl compounds (acetylacetone and Meldrum's acid) are also successfully employed as soft carbon nucleophiles. Studies for mechanism elucidation are also reported, pointing toward the existence of carbocationic intermediates and two working reaction pathways for the obtention of the allylic substitution product.
- Trillo, Paz,Baeza, Alejandro,Najera, Carmen
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p. 7344 - 7354
(2012/10/30)
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- Intermolecular amination of allyl alcohols with sulfamates: Effective utilization of mercuric catalyst
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Herein, we describe the intermolecular amination of allyl alcohols with sulfamates, which have been underutilized as nitrogen nucleophiles for allylic amination. Methyl sulfamate is a good nucleophile in the presence of mercuric triflate and efficiently generates monoallylation products in excellent yield at room temperature. Furthermore, the solid-supported mercuric catalyst silaphenyl mercuric triflate also showed remarkable catalytic activity for the allylic amination. Intermolecular amination of allyl alcohol with sulfamate as a modifiable nitrogen nucleophile is presented. Mercuric reagents act as highly efficient catalyst for the allylic amination, and the procedure was applied to the preparation of various amine derivatives. In many cases, the reaction can be carried out at room temperature and is applicable to a large range of allylic alcohols to give the monoallylated products in excellent yield. Copyright
- Yamamoto, Hirofumi,Ho, Elisabeth,Sasaki, Ikuo,Mitsutake, Mizuho,Takagi, Yuichi,Imagawa, Hiroshi,Nishizawa, Mugio
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supporting information; experimental part
p. 2417 - 2420
(2011/06/10)
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- A new selena-aza-payne-type rearrangement of aziridinylmethyl tosylates mediated by tetraselenotungstate
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Tetraselenotungstate 1 reacts with simple (N-tosylaziridinyl)-methyl tosylate derivatives to give allylamine derivatives as the only products by an unprecedented selena-aza-Payne-type rearrangement. When the methodology is extended to disubstituted (N-tos
- Sureshkumar, Devarajulu,Koutha, Srinivasamurthy,Chandrasekaran, Srinivasan
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p. 4543 - 4551
(2008/02/12)
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- Tellurium-triggered formation of racemic and non-racemic allylic amines from aziridinemethanol derivatives
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Sharpless epoxidation, aminohydroxylation, and aziridination procedures provide substrates for the tellurium-triggered synthesis of racemic and non-racemic allylic amines under phase-transfer conditions.
- Chao, Bin,Dittmer, Donald C.
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p. 5789 - 5791
(2007/10/03)
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- Diastereoselective addition reactions of racemic chiral vinyl sulfimides
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S-Aryl S-vinyl sulfimides are prepared by a new method via Horner-Wadsworth-Emmons reagents generated in situ. Lewis acid-catalysed Diels-Alder reaction of S-ethenyl-S-phenyl-N-tosylsulfimide with cyclopentadiene leads to the endo anti product with good d
- Rayner, Charlotte P.,Clark, Andrew J.,Rooke, Stuart M.,Sparey, Tim J.,Taylor, Paul C.
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- Allylic amine formation by imination of allylic tellurides
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The imination of allylic phenyl tellurides with [N-(p-toluenesulfonyl)imino]phenyliodinane or chloramine-T affords the corresponding allylic amines via [2,3]sigmatropic rearrangement of the tellurimide intermediates in high yields. Application to chiral cinnamyl 2-(1-dimethylaminoethyl)ferrocenyl telluride results in the formation of the corresponding chiral allylic amine, 3-phenyl-3-tosylaminopropene, with 93% ee.
- Nishibayashi, Yoshiaki
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p. 6725 - 6728
(2007/10/02)
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- Allylic Selenides in Organic Synthesis: New Methods for the Synthesis of Allylic Amines
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Oxidative rearrangement of allylic selenides in the presence of various amine nucleophiles provides synthetic access to a variety of allylic amine derivatives.The stereochemical outcome of these reactions has been investigated, and is consistent with a -sigmatropic rearrangement mechanism.Several D-α-amino acids and racemic β,γ-unsaturated α-amino acids were prepared in this manner.A variant of this process employing an achiral allylic selenide and chiral amide afforded protected allylic amines in low diastereoisomeric excess.
- Shea, Regan G.,Fitzner, Jeffrey N.,Fankhauser, John E.,Spaltenstein, Andreas,Carpino, Philip A.,et al.
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p. 5243 - 5252
(2007/10/02)
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- SYNTHESIS OF PROTECTED ALLYLAMINES VIA PALLADIUM-CATALYZED AMIDE ADDITION TO ALLYLIC SUBSTRATES
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Palladium-catalyzed reaction of allylic substrates with sodium p-toluenesulfonamide leads to the N-allylic-p-toluenesulfonamides.The reaction takes place with retention of configuration at the allylic carbon.
- Bystroem, Styrbjoern E.,Aslanian, Robert,Baeckvall, Jan-E.
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p. 1749 - 1752
(2007/10/02)
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- SYNTHESIS OF PROTECTED ALLYLIC AMINES FROM ALLYLIC PHENYL SELENIDES: IMPROVED CONDITIONS FOR THE CHLORAMINE T OXIDATION OF ALLYLIC PHENYL SELENIDES
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Anhydrous chloramine T in methanol is a highly effective reagent for the conversion of allylic phenyl selenides to the corresponding rearranged N-allylic-p-toluenesulfonamides.The reaction presumably proceeds via an allylic selenimide intermediate which undergoes -sigmatropic rearrangement.
- Fankhauser, John E.,Peevey, Richard M.,Hopkins, Paul B.
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