- Catalytic Diastereo- and Enantioconvergent Synthesis of Vicinal Diamines from Diols through Borrowing Hydrogen
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We present herein an unprecedented diastereoconvergent synthesis of vicinal diamines from diols through an economical, redox-neutral process. Under cooperative ruthenium and Lewis acid catalysis, readily available anilines and 1,2-diols (as a mixture of diastereomers) couple to forge two C?N bonds in an efficient and diastereoselective fashion. By identifying an effective chiral iridium/phosphoric acid co-catalyzed procedure, the first enantioconvergent double amination of racemic 1,2-diols has also been achieved, resulting in a practical access to highly valuable enantioenriched vicinal diamines.
- Feng, Wei,Gao, Taotao,Lau, Kai Kiat,Lin, Yamei,Pan, Hui-Jie,Yang, Binmiao,Zhao, Yu
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supporting information
p. 18599 - 18604
(2021/08/09)
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- Direct, high-yielding, one-step synthesis of vic-diols from aryl alkynes
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An unprecedented, high yielding, direct, one-step synthesis of vic-diols from alkynes has been developed via metal-free, open-to-air dihydroboration with ammonia borane. The electronics of the alkyne and the reaction stoichiometry are critical for obtaining optimal yields of the 1,2-diol.
- Ramachandran, P. Veeraraghavan,Drolet, Michael P.
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supporting information
p. 967 - 970
(2018/02/14)
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- Developing a Bench-Scale Green Diboration Reaction toward Industrial Application
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We report a new methodology for the organocatalytic diboration reaction using inexpensive, sustainable, nontoxic, commercially available halogen salts. This is an educative manuscript for the transformation of laboratory scale reactions into a sustainable approach of appeal to industry.
- Farre, Albert,Briggs, Rachel,Pubill-Ulldemolins, Cristina,Bonet, Amadeu
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supporting information
p. 4775 - 4782
(2017/10/27)
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- Cp2TiCl2-catalyzed cycloboration of α-olefins with PhBCl2in the synthesis of 2-alkyl(aryl,benzyl)-1-phenylboriranes
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A one-pot method for the synthesis of 2-alkyl(aryl, benzyl)-1-phenylboriranes has been developed via the reaction of α-olefins with PhBCl2in the presence of Cp2TiCl2as the catalyst. The method implies the formation of boriranes as the result of transmetalation of titanacyclopropane intermediates generated in the reaction of α-olefins with Cp2TiCl2. Individual 1-phenyl-2-substituted boriranes were isolated and their structures confirmed by NMR spectral methods.
- Khusainova, Liliya I.,Khafizova, Leila O.,Tyumkina, Tatyana V.,Ryazanov, Kirill S.,Dzhemilev, Usein M.
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- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
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An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
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p. 12634 - 12637
(2017/12/02)
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- Scope and mechanism of the Pt-catalyzed enantioselective diboration of monosubstituted alkenes
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The Pt-catalyzed enantioselective diboration of terminal alkenes can be accomplished in an enantioselective fashion in the presence of chiral phosphonite ligands. Optimal procedures and the substrate scope of this transformation are fully investigated. Reaction progress kinetic analysis and kinetic isotope effects suggest that the stereodefining step in the catalytic cycle is olefin migratory insertion into a Pt-B bond. Density functional theory analysis, combined with other experimental data, suggests that the insertion reaction positions platinum at the internal carbon of the substrate. A stereochemical model for this reaction is advanced that is in line both with these features and with the crystal structure of a Pt-ligand complex.
- Coombs, John R.,Haeffner, Fredrik,Kliman, Laura T.,Morken, James P.
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p. 11222 - 11231
(2013/08/23)
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- Metal-free dihydroxylation of alkenes using cyclobutane malonoyl peroxide
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Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 → 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and γ-lactones.
- Jones, Kevin M.,Tomkinson, Nicholas C. O.
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experimental part
p. 921 - 928
(2012/02/16)
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- Synthesis and reaction of phthaloyl peroxide derivatives, potential organocatalysts for the stereospecific dihydroxylation of alkenes
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To improve the synthesis and reactivity of phthaloyl peroxide derivatives a method has been developed using sodium percarbonate and phthaloyl chlorides. The reactions of the new phthaloyl peroxide derivatives with trans-stillbene as well as the improved reactivity of 3,4-dichlorophthaloyl peroxide with a variety of alkenes are reported.
- Yuan, Changxia,Axelrod, Abram,Varela, Michael,Danysh, Laura,Siegel, Dionicio
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supporting information; experimental part
p. 2540 - 2542
(2011/06/21)
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- Alkene syn dihydroxylation with malonoyl peroxides
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Cyclopropyl malonoyl peroxide (1), which can be prepared in a single step from the commercially available diacid, is an effective reagent for the dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (40-93%). With 1,2-disubstituted alkenes, the reaction proceeds with syn selectivity (3:1 to >50:1). A mechanism consistent with the experimental findings that is supported by oxygen-labeling studies is proposed.
- Griffith, James C.,Jones, Kevin M.,Picon, Sylvain,Rawling, Michael J.,Kariuki, Benson M.,Campbell, Matthew,Tomkinson, Nicholas C. O.
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supporting information; experimental part
p. 14409 - 14411
(2010/12/24)
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- Biocatalytic asymmetric dihydroxylation of conjugated mono-and poly-alkenes to yield enantiopure cyclic cis-diols
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Dioxygenase-catalysed asymmetric dihydroxylation, of a series of conjugated monoalkenes and polyenes, was found to yield the corresponding monols and 1,2-dihydrodiols. The diol metabolites were obtained from monosubstituted, gem-disubstituted, cis-disubstituted, and trisubstituted alkene substrates, using whole cells of Pseudomonas putida strains containing toluene and naphthalene dioxygenases. Dioxygenase selection and alkene type were established as important factors, in the preference for dioxygenase-catalysed 1,2-dihydroxylation of conjugated alkene or arene groups, and monohydroxylation at benzylic or allylic centres. Competition from allylic hydroxylation of methyl groups was observed only when naphthalene dioxygenase was used as biocatalyst. The structures, enantiomeric excess values and absolute configurations of the bioproducts, were determined by a combination of stereochemical correlation, spectroscopy (NMR and CD) and X-ray diffraction methods. cis-1,2-Diol metabolites from arenes, cyclic alkenes and dienes were generally observed to be enantiopure (> 98% ee), while 1,2-diols from acyclic alkenes had lower enantiomeric excess values (2-symmetrical ketone.
- Boyd, Derek R.,Sharma, Narain D.,Bowers, Nigel I.,Brannigan, Ian N.,Groocock, Melanie R.,Malone, John F.,McConville, Gareth,Allen, Christopher C. R.
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p. 1081 - 1089
(2007/10/03)
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- Stereoelectronic effects in the DIBAL reduction of aryl-1,2-ethanediol benzylidene acetals
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Reduction of benzylidene acetal 8 with DIBAL-H selectively gave 4 in 89% yield. 1-Aryl-1,2-diol benzylidene acetals display unusual regioselectivity with electron withdrawing groups on the aryl group.
- Gauthier Jr., Donald R,Szumigala Jr., Ronald H,Armstrong III, Joseph D,Volante
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p. 7011 - 7014
(2007/10/03)
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- Bismuth(III)-catalyzed oxidative cleavage of aryl epoxides: substituent effects on the kinetics of the oxidation reaction
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Bismuth(III)mandelate catalyzes the oxidative C-C bond cleavage of a series of styrene epoxides in DMSO, to the corresponding aryl carboxylic acids.The reaction is accelerated in the presence of electron-donating groups substituting the phenyl ring.A good Hammet correlation of log kobs versus ? has been obtained, with a ρ of -1.08.Key words: Bismuth; Aryl epeoxide cleavage; Oxidation; Substituent effects; Bi(III) catalysis; Hammet correlation
- Boisselier, Veronique Le,Dunach, Elisabet,Postel, Michele
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p. 119 - 124
(2007/10/02)
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