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Ni-Catalyzed Carboxylation of Aziridines en Route to β-Amino Acids
A Ni-catalyzed reductive carboxylation of N-substituted aziridines with CO2 at atmospheric pressure is disclosed. The protocol is characterized by its mild conditions, experimental ease, and exquisite chemo- and regioselectivity pattern, thus unlocking a new catalytic blueprint to access β-amino acids, important building blocks with considerable potential as peptidomimetics.
Davies, Jacob,Janssen-Müller, Daniel,Zimin, Dmitry P.,Day, Craig S.,Yanagi, Tomoyuki,Elfert, Jonas,Martin, Ruben
supporting information
p. 4949 - 4954
(2021/04/07)

Palladium-Catalyzed Oxidative Allylation of Sulfoxonium Ylides: Regioselective Synthesis of Conjugated Dienones
The first examples of palladium-catalyzed allylic C-H oxidative allylation of sulfoxonium ylides to afford the corresponding conjugated dienones with moderate to good yields have been established. The features of this novel conversion include mild reaction conditions, wide substrate scope, and excellent regioselectivity.
Li, Chunsheng,Li, Meng,Zhong, Wentao,Jin, Yangbin,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
supporting information
p. 872 - 875
(2019/05/16)

Palladium-catalyzed tandem isomerization/hydrothiolation of allylarenes
Herein we report a tandem olefin migration/hydrothiolation of allyl benzenes facilitated by an in situ generated palladium hydride. A catalyst system composed of palladium acetate and bidentate ligand dtbpx (1,2-bis(di-tert-butylphosphinomethyl)benzene in the presence of catalytic amounts of triflic acid led to the tandem transformation, which furnished benzylic thioethers. The reaction exhibits high regioselectivity and can be conducted under mild conditions. The robustness of the catalyst is displayed through reactions with coordinating thiols.
Kathe, Prasad M.,Fleischer, Ivana
supporting information
p. 2213 - 2217
(2019/03/26)

Cross-Coupling Reactions of Aryldiazonium Salts with Allylsilanes under Merged Gold/Visible-Light Photoredox Catalysis
A method for the cross-coupling reactions of aryldiazonium salts with trialkylallylsilanes via merged gold/photoredox catalysis is described. The reaction is proposed to proceed through a photoredox-promoted generation of an electrophilic arylgold(III) intermediate that undergoes transmetalation with allyltrimethylsilane to form allylarenes.
Akram, Manjur O.,Mali, Pramod S.,Patil, Nitin T.
supporting information
p. 3075 - 3078
(2017/06/23)

Flow Metal-Free Ar-C Bond Formation via Photogenerated Phenyl Cations
A convenient photochemical flow protocol for the formation of aryl-carbon bonds via photogenerated phenyl cations has been developed. A wide range of phenylated products, including biaryls, allylarenes, 2-arylacetals and benzyl γ-lactones, was smoothly synthesized in satisfactory yields under metal-free conditions. The adoption of a flow reactor often allowed us to adopt higher concentrations of substrates and shorter irradiation times compared to those usually employed in batch systems.
Bergami, Matteo,Protti, Stefano,Ravelli, Davide,Fagnoni, Maurizio
supporting information
p. 1164 - 1172
(2016/04/19)

Copper(I)-Catalyzed Allylic Substitutions with a Hydride Nucleophile
An easily accessible copper(I)/N-heterocyclic carbene (NHC) complex enables a regioselective hydride transfer to allylic bromides, an allylic reduction. The resulting aryl- and alkyl-substituted branched α-olefins, which are valuable building blocks for synthesis, are obtained in good yields and regioselectivity. A commercially available silane, (TMSO)2Si(Me)H, is employed as hydride source. This protocol offers a unified alternative to the established metal-catalyzed allylic substitutions with carbon nucleophiles, as no adaption of the catalyst to the nature of the nucleophile is required.
Nguyen, T. N. Thanh,Thiel, Niklas O.,Pape, Felix,Teichert, Johannes F.
p. 2455 - 2458
(2016/06/09)

Palladium-catalyzed aerobic oxidative double allylic C-H oxygenation of alkenes: A novel and straightforward route to α,β-unsaturated esters
A mild tandem oxidative functionalization of allyl aromatic hydrocarbons was accomplished using the catalytic system of Pd(OAc)2/DMA under 1 atm O2. The green twofold C-O bond formation involving double allylic C-H oxygenation unlocks opportunities for markedly different synthetic strategies. Moreover, the reaction affords aryl α,β-unsaturated esters directly from readily available terminal olefins in moderate to good yields with excellent chemo- and stereoselectivities.
Yang, Wanfei,Chen, Huoji,Li, Jianxiao,Li, Chunsheng,Wu, Wanqing,Jiang, Huanfeng
supporting information
p. 9575 - 9578
(2015/06/08)

Trifluoromethylchlorosulfonylation of alkenes: Evidence for an inner-sphere mechanism by a copper phenanthroline photoredox catalyst
Abstract A visible-light-mediated procedure for the unprecedented trifluoromethylchlorosulfonylation of unactivated alkenes is presented. It uses [Cu(dap)2]Cl as catalyst, and contrasts with [Ru(bpy)3]Cl2, [Ir(ppy)2(dtbbpy)]PF6, or eosin Y that exclusively give rise to trifluoromethylchlorination of the same alkenes. It is assumed that [Cu(dap)2]Cl plays a dual role, that is, acting both as an electron transfer reagent as well as coordinating the reactants in the bond forming processes. Double role: The trifluoromethylchlorosulfonylation of unactivated alkenes was developed using [Cu(dap)2]Cl as catalyst (dap=2,9-bis(para-anisyl)-1,10-phenanthroline). [Cu(dap)2]Cl plays a dual role; acting as an electron transfer reagent as well as coordinating the reactants in the bond forming processes.
Bagal, Dattatraya B.,Kachkovskyi, Georgiy,Knorn, Matthias,Rawner, Thomas,Bhanage, Bhalchandra M.,Reiser, Oliver
supporting information
p. 6999 - 7002
(2015/06/08)

Biphilic organophosphorus catalysis: Regioselective reductive transposition of allylic bromides via PIII/PV redox cycling
We report that a regioselective reductive transposition of primary allylic bromides is catalyzed by a biphilic organophosphorus (phosphetane) catalyst. Spectroscopic evidence supports the formation of a pentacoordinate (σ5-P) hydridophosphorane as a key reactive intermediate. Kinetics experiments and computational modeling are consistent with a unimolecular decomposition of the σ5-P hydridophosphorane via a concerted cyclic transition structure that delivers the observed allylic transposition and completes a novel PIII/PV redox catalytic cycle. These results broaden the growing repertoire of reactions catalyzed within the PIII/PV redox couple and suggest additional opportunities for organophosphorus catalysis in a biphilic mode.
Reichl, Kyle D.,Dunn, Nicole L.,Fastuca, Nicholas J.,Radosevich, Alexander T.
p. 5292 - 5295
(2015/05/13)

Environment-friendly, mild and one-step synthesis of Safrole
One-step synthesis of safrole, an important flavor compound, was described. Safrole was prepared by Friedel-Crafts reaction of 1,2-methylenedioxybenzene and allyl alcohol with recyclable Catalysts-Nafion-H. Safrole was obtained with a yield of 80 % and little isosafrole was obtained. The catalyst and excess raw material can be recycled and reused.
Ou, Wenhua,Huang, Hong
p. 1175 - 1176
(2015/02/05)

Gold-catalyzed allylation of aryl boronic acids: Accessing cross-coupling reactivity with gold
A sp3-sp2 C?C cross-coupling reaction catalyzed by gold in the absence of a sacrificial oxidant is described. Vital to the success of this method is the implementation of a bimetallic catalyst bearing a bis(phosphino)amine ligand. A mechanistic hypothesis is presented, and observable transmetalation, C?Br oxidative addition, and C?C reductive elimination in a model gold complex are shown. We expect that this method will serve as a platform for the development of novel transformations involving redox-active gold catalysts.
Levin, Mark D.,Toste, F. Dean
supporting information
p. 6211 - 6215
(2014/06/23)

Palladium-catalyzed regioselective azidation of allylic C-H bonds under atmospheric pressure of dioxygen
A palladium-catalyzed allylic azidation of alkenes with sodium azide under atmospheric pressure of dioxygen was developed. This methodology provides a new efficient and simple route for accessing allylic azides. Furthermore, the one-pot process consisting of Pd-catalyzed allylic azidation of alkenes and Cu-catalyzed 1,3-dipolar cycloaddition led directly to the 1,2,3-triazole from the alkene. The formed allylic azide can be also in situ reduced to the allylic amine or oxidized to the alkenyl nitrile. the Partner Organisations 2014.
Chen, Huoji,Yang, Wanfei,Wu, Wanqing,Jiang, Huanfeng
supporting information
p. 3340 - 3343
(2014/05/20)

Palladium-catalyzed aerobic oxidative allylic C-H arylation of alkenes with polyfluorobenzenes
An aerobic oxidative cross-coupling reaction of alkenes with polyfluorobenzenes, through palladium-catalyzed allylic C-H activation, is reported. This attractive route provides a new way to forge allylic C-C bonds of valuable products, in good yields, with high regioselectivity.
Jiang, Huanfeng,Yang, Wanfei,Chen, Huoji,Li, Jianxiao,Wu, Wanqing
supporting information
p. 7202 - 7204
(2014/07/07)

Expeditious synthesis of bioactive allylphenol constituents of the genus Piper through a metal-free photoallylation procedure
Nine bioactive allylphenol (anisole) derivatives (e.g. eugenol, safrole and asaricin) present in several plants of the genus Piper have been synthesized in medium to high yield via aryl cation intermediates. This expeditious metal-free procedure involves the irradiation of the corresponding chlorophenols or chloroanisoles in a polar solvent (MeCN or, better, TFE or aqueous acetonitrile) in the presence of allyltrimethylsilane. Estragole has also been synthesized starting from the corresponding fluoroderivative and diazonium salt, though in a lower yield. The Royal Society of Chemistry 2005.
Protti, Stefano,Fagnoni, Maurizio,Albini, Angelo
p. 2868 - 2871
(2007/10/03)

A new ruthenium-catalyzed cleavage of a carbon-carbon triple bond: Efficient transformation of ethynyl alcohol into alkene and carbon monoxide
We report a new and efficient ruthenium-catalyzed reaction that transforms ethynyl alcohol into alkene and carbon monoxide. The most efficient catalysts are TpRu(PPh3)(CH3CN)2PF6 (10 mol %) and lithium triflate
Datta, Swarup,Chang, Chia-Lung,Yeh, Kuo-Liang,Liu, Rai-Shung
p. 9294 - 9295
(2007/10/03)

Rhodium- and iridium-catalyzed allylation of electron-rich arenes with allyl tosylate
The allylation of electron-rich arenes with allyl tosylate proceeded at 0°C in the presence of [Rh(nbd)(CH3CN)2]PF 6. Various oxygenated arenes were allylated with high para-selectivity in almost all cases. Especially in t
Tsukada, Naofumi,Yagura, Yasushige,Sato, Tetsuo,Inoue, Yoshio
p. 1431 - 1434
(2007/10/03)

An Internally Activated Tin Hydride with Enhanced Reducing Ability
Tin hydride 1 is activated for nucleophilic hydride transfer and also for radical chain reduction, depending on solvent.The nucleophilic hydride pathway is favored in methanol, and 1 can be used as a selective reducing agent for ketones.Simple ketones are not reduced in aprotic solvents, but β-hydroxy ketones are activated internally by the hydroxyl group and can be reduced in THF with good control of stereochemistry, as in the conversion from 7 to 9 (30:1 9:8).A catalytic version of the nucleophilic hydride reductions in methanol has been developed using PhSiH3 as the stoichiometric hydride source.Radical chain dehalogenations can also be achieved with 1 at room temperature and without added radical initiators.Simple xanthates are not reduced efficiently in the absence of an initiator, but the reaction proceeds in the presence of AIBN.
Vedejs, E.,Duncan, S. M.,Haight, A. R.
p. 3046 - 3050
(2007/10/02)

Studies on the constituents of the plants of Illicium species. III. Structure elucidations of novel phytoquinoids, illicinones and illifunones from Illicium tashiroi Maxim. and I. arborescens Hayata
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yakushijin k.,tohshima t.,kitagawa e.,et al.
p. 11 - 22
(2007/10/02)

lithium: A New Reagent for Carbonyl Reductive Vinylation
The direct transformation of a carbonyl compound into a vinyl compound (i.e., cyclohexanone vinylcyclohexane) is now possible with use of the new reagent described in this paper: lithium, followed by protodesilylation.
Wilson, Stephen R.,Shedrinsky, Alexander
p. 1983 - 1984
(2007/10/02)