- Nickel Catalyzed Intermolecular Carbonyl Addition of Aryl Halide
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In this study, we develop a nickel-catalyzed carbonyl arylation reaction employing aldehydes with aryl and allyl halides. Various aryl, α,β-unsaturated aldehyde and aliphatic aldehydes can be converted into their corresponding secondary alcohols in moderate-to-high yields. In addition, we extended this approach to develop an asymmetric reductive coupling reaction that combines nickel salts with chiral bisoxazoline ligands to give secondary alcohols with moderate enantioselectivity.
- Ishida, Seima,Suzuki, Hiroyuki,Uchida, Seiichiro,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 7483 - 7487
(2019/12/11)
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- Catalyst-Controlled 1,2- and 1,1-Arylboration of α-Alkyl Alkenyl Arenes
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Two methods are reported for the 1,2- and 1,1-arylboration of α-methyl vinyl arenes. In the case of 1,2-arylboration, the formation of a quaternary center occurred through a rare cross-coupling reaction of a tertiary organometallic complex. 1,1-Arylboration was enabled by catalyst optimization and occurred through a β-hydride elimination/reinsertion cascade. Enantioselective variants of both processes are presented as well as mechanistic investigations.
- Bergmann, Allison M.,Dorn, Stanna K.,Smith, Kevin B.,Logan, Kaitlyn M.,Brown, M. Kevin
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supporting information
p. 1719 - 1723
(2019/01/14)
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- Enantioselective CuH-Catalyzed Reductive Coupling of Aryl Alkenes and Activated Carboxylic Acids
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A new method for the enantioselective reductive coupling of aryl alkenes with activated carboxylic acid derivatives via copper hydride catalysis is described. Dual catalytic cycles are proposed, with a relatively fast enantioselective hydroacylation cycle followed by a slower diastereoselective ketone reduction cycle. Symmetrical aryl carboxyclic anhydrides provide access to enantioenriched α-substituted ketones or alcohols with excellent stereoselectivity and functional group tolerance.
- Bandar, Jeffrey S.,Ascic, Erhad,Buchwald, Stephen L.
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supporting information
p. 5821 - 5824
(2016/06/09)
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- Rhodium-catalysed tandem hydroformylation/arylation reaction with boronic acids
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A new efficient multicatalytic process involving a single catalyst to promote tandem hydroformylation/arylation reactions is disclosed. The effect of the rhodium ligand was evaluated and the rhodium/triphenylphosphine catalytic system was selected to apply the methodology to different olefins and boronic acids. High yields (up to 89%) and good to excellent isomer ratios (up to 98:2) were achieved using aryl olefins as starting materials. This new methodology allows the preparation of secondary alcohols, from simple olefins, and paves the way for the synthesis of high-value products, namely vinylindole and anethole derivatives.
- Almeida, Ana R.,Dias, Roberto D.,Monteiro, Carlos J. P.,Abreu, Artur R.,Gois, Pedro M. P.,Bayon, J. Carles,Pereira, Mariette M.
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supporting information
p. 1223 - 1228
(2014/05/06)
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- Alkene Oxyalkylation Enabled by Merging Rhenium Catalysis with Hypervalent Iodine(III) Reagents via Decarboxylation
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Rhenium-catalyzed oxyalkylation of alkenes is described, where hypervalent iodine(III) reagents derived from widely occurring aliphatic carboxylic acids were used as, for the first time, not only an oxygenation source but also an alkylation source via decarboxylation. The reaction also features a wide substrate scope, totally regiospecific difunctionalization, mild reaction conditions, and ready availability of both substrates. Mechanistic studies revealed a decarboxylation/radical-addition/cation-trapping cascade operating in the reaction.
- Wang, Yin,Zhang, Lei,Yang, Yunhui,Zhang, Ping,Du, Zhenting,Wang, Congyang
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supporting information
p. 18048 - 18051
(2014/01/06)
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- Role of free space and conformational control on photoproduct selectivity of optically pure α-alkyldeoxybenzoins within a water-soluble organic capsule
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Optically pure α-alkyl deoxybenzoins resulting in products of Norrish Type I and Type II reactions upon excitation has been investigated within the octa acid (OA) capsule in water. The product distribution was different from that in an organic solvent and was also dependent on the length of the α-alkyl chain. Most importantly, a rearrangement product not formed in an organic solvent arising from the triplet radical pair generated by Norrish Type I reaction was formed, and its yield was dependent on the alkyl chain length. In an organic solvent, since the cage lifetime is shorter than the time required for intersystem crossing (ISC) of the triplet radical pair to the singlet radical pair the recombination with or without rearrangement of the primary radical pair (phenylacetyl and benzyl) does not occur. Recombination without rearrangement within the capsule as inferred from monitoring the racemization of the optically pure α-alkyl deoxybenzoins suggesting the capsule's stability for at least 10-8 s (the time required for ISC) is consistent with our previous photophysical studies that showed partial opening and closing of the capsule in the time range of microseconds.
- Kulasekharan, Revathy,Maddipatla, Murthy V. S. N.,Parthasarathy, Anand,Ramamurthy
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p. 942 - 949
(2013/04/10)
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- Diastereoselective friedel-crafts alkylation of indoles with chiral α-phenyl benzylic cations. Asymmetric synthesis of anti-1,1,2- triarylalkanes
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(Chemical Equation Presented) The reactions of chiral benzyl carbocations bearing α-phenyl substituents with N-sulfonylated indoles afford 1,1,2-triarylalkanes with antiselectivities. This outcome is a reversal of facial diastereoselectivity relative to B
- Chung, John Y. L.,Mancheno, Danny,Dormer, Peter G.,Variankaval, Narayan,Ball, Richard G.,Tsou, Nancy N.
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supporting information; experimental part
p. 3037 - 3040
(2009/05/07)
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- Cadmium-mediated carbonyl benzylation in tap water
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Zn/CdCl2 has been developed as a mediator in the benzylation of various aldehydes in tap water affording the corresponding alcohols in moderate to good yields. The addition of a catalytic amount of InCl3 increases the yield of benzylation product significantly. It can selectively mediate the benzylation of aldehydes in the presence of ketones. A mechanism involving the formation of a cation π-complex is proposed based on the experimental facts. Georg Thieme Verlag Stuttgart.
- Zhou, Cunliu,Wang, Zhiyong
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p. 1649 - 1655
(2007/10/03)
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- Lewis base-catalyzed addition of trialkylaluminum compounds to epoxides
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A novel concept for catalytic epoxide alkylation has been developed. Lewis bases like phosphanes, arsanes, stibanes, and sulfides were found to catalyze the alkylation of symmetrical epoxides with trialkylaluminum compounds very effectively at a 5 mol % level. Cyclic as well as acyclic epoxides were readily alkylated in good yields. In reactions with terminal epoxides a significant enhancement of rate and/or regioselectivity was noted in the Lewis base-catalyzed process. Coordination of the Lewis base to the Lewis acidic aluminum reagent was proved by 27Al and 31p NMR spectroscopy and is proposed to form a more nucleophilic alkylating agent.
- Schneider, Christoph,Brauner, J?rg
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p. 4445 - 4450
(2007/10/03)
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- Stereoselective synthesis of 1,3-diol from β-hydroxyacylsilane via rearrangement of phenyl group from silicon to carbon
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Treatment of β-hydroxyacyldimethylphenylsilanes with potassium fluoride in DMSO gave 1,3-diols stereoselectively via migration of phenyl group on silicon.
- Morihata, Kohdai,Horiuchi, Yoshihiro,Taniguchi, Masahiko,Oshima, Koichiro,Utimoto, Kiitiro
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p. 5555 - 5558
(2007/10/03)
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- Ligand effects on diastereoselective addition of organocerium reagents to aldehydes and cyclic ketones
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A new class of chiral dialkoxy- and diaryloxyorganocerium reagent has been prepared and the diastereoselectivity of carbonyl addition reactions has been compared with that of conventional organocerium reagents.
- Greeves, Nicholas,Lyford, Lisa,Elizabeth Pease
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p. 285 - 288
(2007/10/02)
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- On the Reduction of Enol Acetates and Enolates derived from α-Chiral Ketones with Lithium Tetrahydridoaluminate
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The Z- and E-isomers of 1-acetaoxy-1,2-diphenylprop-1-ene (1) and (2), and of 3-acetoxy-4,4-dimethyl-2-phenylpent-2-ene (3) and (4), have been converted into their respective alcohols (1RR,2SS)- and (1RS,2RS)-1,2-diphenylpropan-1-ol (5) and (6), and (1RR,
- Orellana, Guillermo,Perez-Ossorio, Rafael,Quiroga, Maria L.,Sanchez-Asiain, Maria P.
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p. 679 - 682
(2007/10/02)
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- The Mechanism of the Petersen Reaction. Part 2. The Effect of Reaction Conditions, and a New Model for the Addition of Carbanions to Carbonyl Derivatives in the Absence of Chelation Control
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The stereochemistry of the Petersen olefination reaction between PhHSiMe3 and PhCHO has been studied under a wide variety of conditions with excellent reproducibility and extremely high yields.The effects of counterion, solvent, added salts, variation of the carbanion-forming base, and temperature have been investigated.The product stereochemistry is remarkably insensitive to the reaction conditions.The results lead to a new method of analysis of steric approach control based on the angle of approach as defined by Dunitz and Baldwin.The method involves analysis of 'primary' and 'secondary' transition-state interactions.This analysis should be generally applicable to carbanion additions in which chelation is insignificant.
- Bassindale, Allan R.,Ellis, Richard J.,Lau, Juliana C.-Y.,Taylor, Peter G.
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p. 593 - 598
(2007/10/02)
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- Stereoselective Addition of Organotitanium Reagents to Carbonyl Compounds
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Titanation of alkyllithium or -magnesium compounds using ClTi(OR)3 results in reagents which show markedly increased diastereofacial selectivity (80 - 90percent) in reactions with α-chiral aldehydes or ketones.Titanation is also the method of choice in Grignard-type additions to substituted cyclohexanones; CH3Ti(OCHMe2)3 (6a) adds predominantly from the equatorial direction, while allyltitanium reagents 11b and 12 show axial preference.Crotyltitanium compounds react with carbonyl compounds to afford primarily adducts having anti-configuration, a process which is of particular value in case of ketones (anti/syn ratios up to 99:1).Titanation of (trimethylsilyl)allyllithium (48) with Ti(OCHMe2)4 reverses regioselectivity in reactions with aldehydes and ketones, β-hydroxy silanes 50 being the only observed products.These have anti-configuration and can be converted either into Z- or E-dienes using the Peterson elimination under basic or acidic conditions, respectively.
- Reetz, Manfred T.,Steinbach, Rainer,Westermann, Juergen,Peter, Roland,Wenderoth, Bernd
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p. 1441 - 1454
(2007/10/02)
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- STEREOCHEMICAL STUDIES OF THE ELECTROLYTIC REACTIONS OF ORGANIC COMPOUNDS. PART 18. COMPARATIVE STUDY OF HYDROGENATION OF METAL-BLACK CATHODES AND CATALYSTS.
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Stereoselective hydrogenation on metal-black cathodes and catalysts, which were prepared by electrodeposition under the same conditions, was comparatively investigated. Stereoisomeric ratios of alcohols formed from the ketones on the Pd- and Pt-black cathodes seemed to be almost equal to those on the corresponding metal-black catalysts, while the yields were quite different between the cathodic and catalytic hydrogenations. On the other hand, results of the hydrogenation of the acetylenes on the cathodes were also different, in not only the yield but also the isomeric ratio, from those on the catalysts. In addition to stereoselectivity, relative hydrogenation rates between cis- and trans-olefins were compared in both the cathodic and catalytic hydrogenations.
- Nonaka,Takahashi,Fuchigami
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p. 2584 - 2583
(2007/10/02)
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- A NEW METHOD FOR THE SYNTHESIS OF β-HYDROXYESTERS BY USING METALLIC TIN
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Metallic tin or activated metallic tin, prepared by reduction of stannous chloride with lithium aluminum hydride, smoothly reacts with α-haloesters to yield tin enolates, which in turn react with carbonyl compounds under mild conditions to give, after hydrolysis, β-hydroxyesters in high yields.
- Harada, Taira,Mukaiyama, Teruaki
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p. 161 - 164
(2007/10/02)
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- Reactivite des arenes chrome tricarbonyle. Action sur les derives carbonyles
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Complexation of a Cr(CO)3 unit with an aromatic hydrocarbon activates the benzylique position of the latter towards alkaline attack and the obtained carbanion reacts with carbonyl compounds, yielding a complexed alcohol.This reaction may be used to functionalize the benzylique position of an aromatic hydrocarbon.
- Lebibi, Jacques,Brocard, Jacques,Couturier, Daniel
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p. 357 - 361
(2007/10/02)
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- STEREOCHEMISTRY OF THE OPENING OF THE CYCLOPROPANE RING BY MERCURY SALTS IN trans-1,2-DIARYLCYCLOPROPANES
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The stereochemistry of the opening of the small ring under the influence of mercury salts in hydroxyl-containing solvents was investigated in trans-1,2-diphenylcyclopropane and its derivatives containing electron-donating substituents at he para positions of both benzene rings.It was found that the opening of the trimethylene ring at the C1-C3 bond is accompanied by racemization at the point of nucleophilic attack, while the ratio of the diastereomers depends on the nature of the substituents in the benzene ring, on the anion in the mercury salt, and on the solvent.
- Bandaev, S. G.,Sychkova, L. D.,Hantschmann, A.,Shabarov, Yu. S.
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p. 257 - 262
(2007/10/02)
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- Stereochemistry of Ring Opening of trans-1,2-Diphenylcyclopropanes by Mercury(II)salts
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Reaction of trans-1,2-diphenylcyclopropanes 1 and 2 with mercuric salts yields diastereomeric 1,2-diphenylpropanole derivatives.The ratio of erythro and threo diastereomers depends on the nature of substituents and solvent properties.A mechanism is propos
- Bandaev, S. G.,Sabarov, Yu. S.,Hantschmann, A.,Weissenfels, M.
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p. 643 - 648
(2007/10/02)
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