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Palladium-catalyzed intra-molecular olefin insertion reaction of α-alkenyl-α-acyloxytrialkylsilane. Synthesis of optically active carbocycle
Pd-catalyzed intra-molecular olefin insertion/carbonylation reaction of optically active α-alkenyl-α-acyloxysilanes is described. The reactions proceeded in a stereoselective manner to give five- and six-membered optically active carbocycles having (E)-vinylsilane in their side chains. Under CO condition, optically active carbocycles containing one-carbon homologated side chain were produced by Pd-catalyzed tandem olefin insertion-carbonylation reaction.
Sakaguchi, Kazuhiko,Okada, Takuya,Yamada, Takeshi,Ohfune, Yasufumi
p. 3925 - 3928
(2007)
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Metal-Free Domino Oligocyclization Reactions of Enynals and Enynones with Molecular Oxygen
A novel metal-free direct addition of molecular oxygen to the C-C triple bond toward benzannulated oxygen-bridged seven-membered ring systems and aza[3.1.0]bicycle skeletons under 3O2 atmosphere has been described. The reaction proceeds through at least three intramolecular C-O and C-C bond forming steps via green, simple, and unprecedented domino radical processes with high selectivity and good yields.
Abbasi Kejani, Alireza,Khosravi, Hormoz,Rominger, Frank,Balalaie, Saeed,Breit, Bernhard
supporting information
p. 1291 - 1295
(2021/02/20)

Synthesis of Various Bridged Ring Systems via Rhodium-Catalyzed Bridged (3+2) Cycloadditions
Here, we describe the rhodium-catalyzed bridged (3+2) cycloaddition cascade reactions of N-sulfonyl-1,2,3-triazoles, which allowed the efficient diastereoselective construction of various functionalized and synthetically challenging bridged ring systems. This simple, direct transformation had a broad substrate scope and excellent functional group tolerance. The highly strained polycyclic bicyclo[2.2.2]octa[b]indole core of fruticosine was synthesized efficiently using this methodology.
He, Yu-Tao,Hou, Bao-Long,Li, Chuang-Chuang,Li, Li-Xuan,Lin, Xiaohong
supporting information

(2022/01/11)

Methyl Radical Initiated Kharasch and Related Reactions
An improved procedure to run halogen atom and related chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di-tert-butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methyl radicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating greatly product purification by either flash column chromatography or distillation. In addition, remarkably simple and mild reaction conditions (refluxing EtOAc during 30 minutes under normal atmosphere) and a low excess of the radical precursor reagent (2 equivalents) make this protocol particularly attractive for preparative synthetic applications. This initiation procedure has been demonstrated with a broad scope since it works efficiently to add a range of electrophilic radicals generated from iodides, bromides, selenides and xanthates over a range of unactivated terminal alkenes. A diverse set of radical trap substrates exemplifies a broad functional group tolerance. Finally, di-tert-butyl peroxyoxalate (DTBPO) is also demonstrated as alternative source of tert-butoxyl radicals to initiate these reactions under identical conditions which gives gaseous by-products (CO2). (Figure presented.).
Tappin, Nicholas D. C.,Renaud, Philippe
supporting information
p. 275 - 282
(2020/12/07)

Formal Bromine Atom Transfer Radical Addition of Nonactivated Bromoalkanes Using Photoredox Gold Catalysis
Organic transformations mediated by photoredox catalysis have been at the forefront of reaction discovery. Recently, it has been demonstrated that binuclear Au(I) bisphosphine complexes, such as [Au2(μ-dppm)2]X2, are capable of mediating electron transfer to nonactivated bromoalkanes for the generation of a variety of alkyl radicals. The transfer reactions of bromine, derived from nonactivated bromoalkanes, are largely unknown. Therefore, we propose that unique metal-based mechanistic pathways are at play, as this binuclear gold catalyst has been known to produce Au(III) Lewis acid intermediates. The scope and proposed mechanistic overview for the formal bromine atom transfer reaction of nonactivated bromoalkanes mediated by photoredox Au(I) catalysis is presented. The methodology presented afforded good yields and a broad scope which include examples using bromoalkanes and iodoarenes.
Zidan, Montserrat,McCallum, Terry,Swann, Rowan,Barriault, Louis
supporting information
p. 8401 - 8406
(2020/11/03)

Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
Santra, Surojit,Maji, Ujjwal,Guin, Joyram
supporting information
p. 468 - 473
(2020/02/04)

Copper-Catalyzed Dehydrogenative Diels-Alder Reaction
A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
Jiang, Bing,Liang, Qiu-Ju,Han, Yu,Zhao, Meng,Xu, Yun-He,Loh, Teck-Peng
supporting information
p. 3215 - 3219
(2018/06/11)

Annelated Cyclobutanes by Fe-Catalyzed Cycloisomerization of Enyne Acetates
Cationic Fe complexes of the general type [(Ph3P)2Fe(CO)(NO)]X (X=BF4, BArF4) catalyze the redox-neutral cycloisomerization of 1,6- and 1,7-enyneacetates to afford bicyclic cyclobutanes under mild conditions in good yields and diastereoselectivities.
Kramm, Frederik,Teske, Johannes,Ullwer, Franziska,Frey, Wolfgang,Plietker, Bernd
supporting information
p. 13335 - 13338
(2018/09/25)

An improved synthesis of 4-chloro-7H-pyrrolo[2,3-d]pyrimidine
[Figure not available: see fulltext.] An improved seven-step synthesis of 4-chloro-7H-pyrrolo[2,3-d]pyrimidine from dimethyl malonate with 31% overall yield is described. The procedure is operationally simple and practical for the synthesis of the 4-chloro-7H-pyrrolo[2,3-d]pyrimidine building block.
Zhang, Yu-Liu,Xu, Cheng-Tao,Liu, Ting,Zhu, Yong,Luo, Yu
p. 638 - 642
(2018/08/17)

Design and synthesis of malonamide derivatives as antibiotics against methicillin-resistant staphylococcus aureus
Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to humans. Most existing antimicrobial drugs, including the β-lactam and quinoxiline classes, are not effective against MRSA. In this study, we synthesized 24 derivatives of malonamide, a new class of antibacterial agents and potentiators of classic antimicrobials. A derivative that increases bacterial killing and biofilm eradication with low cell toxicity was created.
Su, Jung-Chen,Huang, Yu-Ting,Chen, Chang-Shi,Chiu, Hao-Chieh,Shiau, Chung-Wai
(2018/01/03)

Catalytic C?C Bond Formation Using a Simple Nickel Precatalyst System: Base- and Activator-Free Direct C-Allylation by Alcohols and Amines
A “totally catalytic” nickel(0)-mediated method for base-free direct alkylation of allyl alcohols and allyl amines is reported. The reaction is selective for monoallylation, uses an inexpensive NiII precatalyst system, and requires no activating reagents to be present.
Sweeney, Joseph B.,Ball, Anthony K.,Smith, Luke J.
supporting information
p. 7354 - 7357
(2018/05/03)

Selective Hydrogenations and Dechlorinations in Water Mediated by Anionic Surfactant-Stabilized Pd Nanoparticles
We report a facile, inexpensive, and green method for the preparation of Pd nanoparticles in aqueous medium stabilized by anionic sulfonated surfactants sodium 1-dodecanesulfonate 1a, sodium dodecylbenzenesulfonate 1b, dioctyl sulfosuccinate sodium salt 1c, and poly(ethylene glycol) 4-nonylphenyl-3-sulfopropyl ether potassium salt 1d simply obtained by stirring aqueous solutions of Pd(OAc)2 with the commercial anionic surfactants further treated under hydrogen atmosphere for variable amounts of time. The aqueous Pd nanoparticle solutions were tested in the selective hydrogenation reactions of aryl-alcohols, -aldehydes, and -ketones, leading to complete conversion to the deoxygenated products even in the absence of strong Br?nsted acids in the reduction of aromatic aldehydes and ketones, in the controlled semihydrogenation of alkynes leading to alkenes, and in the efficient hydrodechlorination of aromatic substrates. In all cases, the micellar media were crucial for stabilizing the metal nanoparticles, dissolving substrates, steering product selectivity, and enabling recycling. What is interesting is also that a benchmark catalyst like Pd/C can often be surpassed in activity and/or selectivity in the reactions tested by simply switching to the appropriate commercially available surfactant, thereby providing an easy to use, flexible, and practical catalytic system capable of efficiently addressing a variety of synthetically significant hydrogenation reactions.
La Sorella, Giorgio,Sperni, Laura,Canton, Patrizia,Coletti, Lisa,Fabris, Fabrizio,Strukul, Giorgio,Scarso, Alessandro
supporting information
p. 7438 - 7446
(2018/05/29)

Stable Zero-Valent Nickel Nanoparticles in Glycerol: Synthesis and Applications in Selective Hydrogenations
Small (mean diameter, ca. 1.2 nm) and well-dispersed zero-valent nickel nanoparticles (NiNPs) stabilized by cinchona-based alkaloids and TPPTS (tris(3-sulfophenyl)phosphine trisodium salt), were synthesized from the organometallic precursor [Ni(cod)2] in neat glycerol under hydrogen pressure. NiNPs were fully characterized ((HR)-TEM, EDX, XPS, XRD, IR, magnetization), both at solid state and directly from the corresponding colloidal solutions in glycerol due to its negligible vapour pressure. NiNPs dispersed in glycerol were applied in hydrogenation reactions, in particular in semihydrogenation of alkynes to give (Z)-alkenes under satisfactory conditions (3 bar H2, 1 mol% Ni, 100 °C), showing remarkable activity and selectivity. The catalytic phase was recycled at least ten times without loss of activity, affording in each case metal-free organic products. Other functional groups such as nitro, nitrile and formyl groups were efficiently hydrogenated to the corresponding anilines, benzylamines and benzylalcohols respectively (77–95% yields). (Figure presented.).
Reina, Antonio,Favier, Isabelle,Pradel, Christian,Gómez, Montserrat
p. 3544 - 3552
(2018/08/01)

Highly efficient Tsuji-Trost allylation in water catalyzed by Pd-nanoparticles
Palladium nanoparticles stabilized by poly(vinylpyrrolidone) catalyze Tsuji-Trost allylations in water with very high turnover numbers. The di-allylation of methylene active compounds and the allylation of bio-based phenols was performed in high yield. The allylation of lignin showed a high selectivity towards the phenolic OH groups.
Llevot,Monney,Sehlinger,Behrens,Meier
supporting information
p. 5175 - 5178
(2017/07/12)

Cycloaddition Reactions of Cobalt-Complexed Macrocyclic Alkynes: The Transannular Pauson-Khand Reaction
The Pauson-Khand reaction is a powerful tool for the synthesis of cyclopentenones through the efficient [2 + 2 + 1] cycloaddition of dicobalt alkyne complexes with alkenes. While intermolecular and intramolecular variants are widely known, transannular versions of this reaction are unknown and the basis of this study. Macrocyclic enyne and dienyne complexes were readily synthesized by palladium(II)-catalyzed oxidative macrocyclizations of bis(vinyl boronate esters) or ring-closing metathesis reactions followed by complexation with dicobalt octacarbonyl. Several reaction modalities of these macrocyclic complexes were uncovered. In addition to the first successful transannular Pauson-Khand reactions, other intermolecular and transannular cycloaddition reactions included intermolecular Pauson-Khand reactions, transannular [4 + 2] cycloaddition reactions, intermolecular [2 + 2 + 2] cycloaddition reactions, and intermolecular [2 + 2 + 1 + 1] cycloaddition reactions. The structural and reaction requirements for each process are presented.
Karabiyikoglu, Sedef,Boon, Byron A.,Merlic, Craig A.
p. 7732 - 7744
(2017/08/14)

Cyclization of Malonate Derivatives with Iodine(III) Reagents
The cyclization of malonate derivatives by using hypervalent iodine(III) reagents is described. In this reaction, double bonds are dioxygenated to give five-membered lactones in up to 70 % yield with diastereomeric ratios of up to 11:1.
Malmedy, Florence,Wirth, Thomas
supporting information
p. 786 - 789
(2017/02/15)

Enantioselective Isothiourea-Catalysed Michael-Michael-Lactonisation Cascade Reaction for the Synthesis of δ-Lactones and 1,2,3,4-Substituted Cyclopentanes
This manuscript describes the application of α,β-unsaturated acyl ammonium intermediates in a Michael-Michael-lactonisation cascade process to furnish δ-lactones. Generation of α,β-unsaturated acyl ammonium intermediates was achieved upon addition of isothiourea catalyst HyperBTM into α,β-unsaturated acid chlorides. Subsequent reaction with enone-malonates gave access to δ-lactones in 20-64% yield, 72.5:27.5 to 95:5 er and 81:19 to >95:5 dr. Additionally, application of a ring-opening protocol yielded 1,2,3,4-substituted cyclopentanes in 28-77% yield, 76:24 to 98:2 er and 86:14 to >95:5 dr. Interestingly, the highest er was observed at high reaction temperatures, with 70°C proving optimal. This effect was investigated by conducting an Eyring analysis, which indicated that differential activation entropy rather than differential activation enthalpy is responsible for enantiodiscrimination in this process.
Robinson, Emily R. T.,Frost, Aileen B.,Elías-Rodríguez, Pilar,Smith, Andrew D.
p. 409 - 423
(2016/12/24)

I2-Mediated oxidative bicyclization of 4-pentenamines to prolinol carbamates with CO2 incorporating oxyamination of the C=C bond
A metal-free oxyamination reaction of alkenes with ambient CO2 is reported. In the presence of I2 and DBU, CO2 is applied in situ as a protecting group to regulate the nucleophilicity of the amino group and facilitate the bicyclization of 4-pentenamines with high chemoselectivity. Moreover, this reaction provided a feasible approach to prepare prolinol carbamates with good tolerance of functional groups and high efficiency under mild conditions.
Wang, Sheng,Zhang, Xiaowei,Cao, Chengyao,Chen, Chao,Xi, Chanjuan
supporting information
p. 4515 - 4519
(2017/10/13)

Reactivity of (η3-allyl)dicarbonylnitrosyl iron complexes with dimethyl malonate and diisobutyl malonate
In this paper, we describe the reactivity of our previously reported (η3-allyl)dicarbonylnitrosyl iron complexes (1–9). In this context, stoichiometric reactions of 1–9 with dimethyl malonate and di-iso-butyl malonate were carried out. The regioselectivity of the resulting products (10–25) was determined by gas chromatoraphic analysis of reaction mixtures. These products were purified by column chromatography and then structurally characterized by IR, 1H NMR, 13C NMR spectroscopies and mass spectrometry. Effect of different ligands L (L = CO, PPh3, SIMES (1,3-di-tert-butylimidazolium hexafluoro phosphate), BUSI(1,3-bis(2,4,6trimethyl-phenyl)-4,5-dihydro-3H-imidazol-1-ium hexafluorophosphate)) and their influence on the substitution pattern has also been studied. The introduction of variable substituents exhibited diverse reactivities. Generally, it was observed that the reactivity decreased by increasing the size of substituentin (η3-allyl)dicarbonylnitrosyl iron complexes (1–9). Strong impact on the reactivity was observed due to substitution pattern of the allyl moiety. A considerable reduction in the conversion ratio from 81% to 68% was observed in repositioning the substituent from C-3 to C-2 position.
Tabassam, Misbah,Farooq, Amna,Imran, Muhammad,Gillani, Syeda Robina,Saqib, Saima,Mehmood, Zaid,Mitu, Liviu
p. 299 - 312
(2017/12/12)

Synthesis of Enantiomerically Enriched 2-Hydroxymethylalkanoic Acids by Oxidative Desymmetrisation of Achiral 1,3-Diols Mediated by Acetobacter aceti
The stereoselective desymmetrisation of achiral 2-alkyl-1,3-diols is performed by oxidation of one of the two enantiotopic primary alcohol moieties by means of Acetobacter aceti MIM 2000/28 to afford the corresponding chiral 2-hydroxymethyl alkanoic acids (up to 94 % ee). The procedure, carried out in aqueous medium under mild conditions of pH, temperature and pressure, contributes to enlarge the portfolio of enzymatic oxidations available to organic chemists for the development of sustainable manufacturing processes.
Brenna, Elisabetta,Cannavale, Flavia,Crotti, Michele,De Vitis, Valerio,Gatti, Francesco G.,Migliazza, Gaia,Molinari, Francesco,Parmeggiani, Fabio,Romano, Diego,Santangelo, Sara
p. 3796 - 3803
(2016/12/24)

Palladium catalyzed direct benzylation/allylation of malonates with alcohols-: In situ C-O bond activation
High step- and atom-economy are the endlessly pursued in organic and pharmaceutical syntheses. Herein, a new method for directly coupling benzyl/allyl alcohols with malonates via a palladium catalyzed Tsuji-Trost type reaction was developed. The reaction was carried out in an organic carbonate solvent which would activate alcohols in situ, replacing the traditional pre-synthesized carbonates. The new process demonstrated high efficiency, high selectivity and high generality. A wide variety of mono-substituted and bis-substituted malonates were selectively produced under different conditions, and this method represents a more step- and atom-economical and environmentally benign synthetic protocol.
Cao, Xueqin,Zhang, Yugen
supporting information
p. 2638 - 2641
(2016/05/24)

Dimethyl malonate/LHMDS system as a new protocol for generating methyl formate anion (-COOMe) in the condensed-phase Dedicated to Professor Charles H. DePuy (1927-2013)
The treatment of dimethyl malonate with LHMDS in anhydrous THF (condensed-phase) generates, in addition to the expected corresponding lithium enolate, methyl formate anion (or methoxycarbonyl anion, -COOMe) which can react with several electrophiles to give corresponding methoxycarbonyl derivatives by nucleophilic substitution reaction.
Di Bussolo, Valeria,Princiotto, Salvatore,Martinelli, Elisa,Bordoni, Vittorio,Crotti, Paolo
supporting information
p. 1644 - 1647
(2016/04/04)

Rhodium-Catalyzed Stereoselective Intramolecular [5 + 2] Cycloaddition of 3-Acyloxy 1,4-Enyne and Alkene
The first rhodium-catalyzed intramolecular [5 + 2] cycloaddition of 3-acyloxy 1,4-enyne and alkene was developed. The cycloaddition is highly diastereoselective in most cases. Various cis-fused bicyclo[5.3.0]decadienes were prepared stereoselectively. The chirality in the propargylic ester starting materials could be transferred to the bicyclic products with high efficiency. Electron-deficient phosphine ligand greatly facilitated the cycloaddition. Up to three new stereogenic centers could be generated. The resulting diene in the products could be hydrolyzed to enones, which allowed the introduction of more functional groups to the seven-membered ring.
Shu, Xing-Zhong,Schienebeck, Casi M.,Li, Xiaoxun,Zhou, Xin,Song, Wangze,Chen, Lianqing,Guzei, Ilia A.,Tang, Weiping
supporting information
p. 5128 - 5131
(2015/11/03)

Copper(I)-catalyzed intramolecular hydroalkoxylation of unactivated alkenes
A Cu(I)-Xantphos system catalyzed the intramolecular hydroalkoxylation of unactivated terminal alkenes, giving five- and six-membered ring ethers. This system is applicable to both primary and secondary alcohols. A reaction pathway involving the addition of the Cu-O bond across the C-C double bond is proposed. A chiral Cu(I) catalyst system based on the (R)-DTBM-SEGPHOS ligand promoted enantioselective reaction with moderate enantioselectivity.
Murayama, Hiroaki,Nagao, Kazunori,Ohmiya, Hirohisa,Sawamura, Masaya
supporting information
p. 2039 - 2041
(2015/05/13)

Ring-Closing Metathesis with Vicinal Dibromoalkenes as Protected Alkynes: A Synthetic Approach to Macrocyclic Enynes
A new strategy to access macrocyclic enynes was developed. To block undesired ene-yne cyclization pathways, alkynes were protected via bromination and the resultant acyclic vic-(E)-dibromotrienes participated in selective ene-ene ring closing metathesis reactions. Zinc-promoted deprotection of (E)-dibromodienes provided macrocyclic enynes in high yields.
Karabiyikoglu, Sedef,Iafe, Robert G.,Merlic, Craig A.
supporting information
p. 5248 - 5251
(2015/11/18)

Chiral Cationic CpxRu(II) Complexes for Enantioselective Yne-Enone Cyclizations
The cyclopentadienyl (Cp) group is a ligand of great importance for many transition-metal complexes used in catalysis. Cationic CpRuII complexes with three free coordination sites are highly versatile catalysts for many atom-economic transformations. We report the synthesis of a family of CpxRuII complexes with chiral Cp ligands keeping the maximum number of available coordination sites. The cationic members are efficient and selective catalysts for yne-enone cyclizations via formal hetero-Diels-Alder reactions. The transformation proceeds in 1 h at -20 °C and provides pyrans in up to 99:1 er. Unsaturated ester or Weinreb-amide substrates directly yield the iridoid skeleton.
Kossler, David,Cramer, Nicolai
supporting information
p. 12478 - 12481
(2015/10/19)

The synthesis of α-azidoesters and geminal triazides
Three simple methods for the synthesis of geminal triazides are described: Starting from 1) 3-oxocarboxylic acids, 2) iodomethyl ketones, or 3) terminal olefins, a range of triazidomethyl ketones can be constructed under mild oxidative reaction conditions by the use of IBX-SO3K, a sulfonylated derivative of 2-iodoxybenzoic acid (IBX), and NaN3 as an azide source. This is the first report of representatives of this novel class of triazide compounds: Despite their high nitrogen content, the geminal triazides are easy to handle, even when preparative-scale syntheses are performed. (Caution: These procedures still require protective measures!) The triazides are now broadly available for further studies regarding their properties and reactivity. Furthermore, we show how the method can be used to provide α-azidoesters, which are potential building blocks for amino acids. Either/or: Geminal triazides are rapidly constructed with broad scope by the use of oxocarboxylic acids, iodomethyl ketones, or terminal olefins as starting substrates in oxidative azidations with a mild derivative of 2-iodoxybenzoic acid and sodium azide. Along with this little-studied class of organic azides, α-azidoesters were also synthesized.
Klahn, Philipp,Erhardt, Hellmuth,Kotthaus, Andreas,Kirsch, Stefan F.
supporting information
p. 7913 - 7917
(2014/08/05)

Enantioselective diamination with novel chiral hypervalent iodine catalysts
Vicinal diamines constitute one the most important functional motif in organic chemistry because of its wide occurrence in a variety of biological and pharmaceutical molecules. We report an efficient metal-free, highly stereoselective intramolecular diamination using a novel chiral hypervalent iodine reagent together with its application as an efficient catalyst for the synthesis of diamines.
Mizar, Pushpak,Laverny, Aragorn,El-Sherbini, Mohammad,Farid, Umar,Brown, Michael,Malmedy, Florence,Wirth, Thomas
supporting information
p. 9910 - 9913
(2014/08/18)

Palladium nanoparticles bonded to two-dimensional iron oxide graphene nanosheets: A synergistic and highly reusable catalyst for the Tsuji-Trost reaction in water and air
Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble-metal-nanocatalyst- catalyzed reactions. Despite tremendous efforts, developing noble-metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe3O4 and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe3O4 nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe3O4/PEI/rGO) for the Tsuji-Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99% isolated yield, and the turnover frequency reached 2200 h-1. The yield of allylated products was 66% for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5% of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment. Picking up speed: A multifunctional Pd nanocatalyst was synthesized by in situ growth of palladium nanoparticles (PdNPs) and the assembly of Fe3O4 NPs on reduced graphene oxide (rGO) by employing polyethyleneimine as the coupling linker. This nanocatalyst exhibits synergistic catalysis by the amine on the same rGO surface as the PdNPs for acceleration of the Tsuji-Trost reaction in water and air (see figure).
Liu, Jian,Huo, Xing,Li, Tianrong,Yang, Zhengyin,Xi, Pinxian,Wang, Zhiyi,Wang, Baodui
p. 11549 - 11555
(2014/11/07)

Efficient allylation of nucleophiles catalyzed by a bifunctional heterogeneous palladium complex-tertiary amine system
We demonstrate the synergistic catalysis of a silica-supported diaminopalladium complex and a tertiary amine (SiO2/diamine/Pd/ NEt2) as well as synthetic scope of the Tsuji-Trost reaction of 1,3-dicarbonyls, phenols, and carboxylic acids with allyl carbonate and acetates. The synergistic catalysis of SiO2/diamine/Pd/NEt 2 exhibited wide applicability and high activity for the Tsuji-Trost reaction. For example, the reaction of ethyl 3-oxobutanate with allyl methyl carbonate afforded the allylated product in >99% yield at 70 °C for 5 h. The yield of allylated products was 26% for SiO2/diamine/Pd, without immobilization of the tertiary amine group. In the reaction of 1.0 mmol of ethyl 3-oxobutanate using 0.60 μmol of Pd in SiO2/diamine/Pd/NEt 2, the turnover number (TON) of Pd reached up to 1070 within 24 h. Phenols with electron-withdrawing groups, such as nitro and chloro groups, on the para position resulted in high product yields. The SiO2/diamine/ Pd/NEt2 catalyst was reusable at least 4 times without appreciable loss of its activity and selectivity in the reaction of p-chlorophenol. Copyright
Noda, Hiroto,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
p. 973 - 980
(2013/05/08)

One-point binding ligands for asymmetric gold catalysis: Phosphoramidites with a TADDOL-related but acyclic backbone
Readily available phosphoramidites incorporating TADDOL-related diols with an acyclic backbone turned out to be excellent ligands for asymmetric gold catalysis, allowing a number of mechanistically different transformations to be performed with good to outstanding enantioselectivities. This includes [2 + 2] and [4 + 2] cycloadditions of ene-allenes, cycloisomerizations of enynes, hydroarylation reactions with formation of indolines, as well as intramolecular hydroaminations and hydroalkoxylations of allenes. Their preparative relevance is underscored by an application to an efficient synthesis of the antidepressive drug candidate (-)-GSK 1360707. The distinctive design element of the new ligands is their acyclic dimethyl ether backbone in lieu of the (isopropylidene) acetal moiety characteristic for traditional TADDOLs. Crystallographic data in combination with computational studies allow the efficiency of the gold complexes endowed with such one-point binding ligands to be rationalized.
Teller, Henrik,Corbet, Matthieu,Mantilli, Luca,Gopakumar, Gopinadhanpillai,Goddard, Richard,Thiel, Walter,Fuerstner, Alois
supporting information
p. 15331 - 15342
(2012/11/07)

An efficient route to polysubstituted tetrahydronaphthols: Silver-catalyzed [4+2] cyclization of 2-alkylbenzaldehydes and alkenes
Silver bullet: A methodology for stereoselective synthesis of polysubstituted tetrahydronaphthols catalyzed by [Ag+]/NPO has been developed. The reactions proceeded through an unprecedented [4+2] cyclization of 2-(2-formylphenyl)ethanone and an alkene, in both inter- and intramolecular fashion. NPO=pyridine N-oxide. Copyright
Zhu, Shifa,Liang, Renxiao,Jiang, Huanfeng,Wu, Wanqing
supporting information
p. 10861 - 10865
(2013/01/15)

Iridium-catalyzed allylic alkylation reaction with N-aryl phosphoramidite ligands: Scope and mechanistic studies
A series of N-aryl phosphoramidite ligands has been synthesized and applied to iridium-catalyzed allylic alkylation reactions, offering high regio- and enantioselectivities for a wide variety of substrates. These ligands feature the synthetic convenience and good tolerance of the ortho-substituted cinnamyl carbonates. Mechanistic studies, including DFT calculations and X-ray crystallographic analyses of the (π-allyl)-Ir complexes, reveal that the active iridacycle is formed via C(sp2)-H bond activation.
Liu, Wen-Bo,Zheng, Chao,Zhuo, Chun-Xiang,Dai, Li-Xin,You, Shu-Li
supporting information; experimental part
p. 4812 - 4821
(2012/04/23)

A simple diamine as ligand in iron-catalyzed regioselective allylic alkylation
A simple and efficient diamine was found to be an efficient ligand for the iron-catalyzed regioselective allylic alkylation between various allyl carbonates and nucleophiles, affording excellent yields and good regioselectivity (up to 94% and >20:1).
Yu, Chenguang,Zhou, Aihua,He, Jing
p. 8627 - 8630
(2015/02/19)

Two-and three-dimensional liquid-crystal phases from axial bundles of rodlike polyphiles: Segmented cylinders, crossed columns, and ribbons between sheets
Pleated ribbons and bow ties: Rodlike mesogens (see scheme) with swallow-tail side chains arrange axially in ribbonlike bundles. At high temperatures the ribbons rotate, resulting in a novel 3D hexagonal liquid-crystal phase (see picture, left). At lower temperature, rotation locks in giving a structure of crossed aromatic and fluorinated columns (right). On further cooling the ribbons fuse into aromatic sheets with fluorinated columns intercalated. Copyright
Liu, Feng,Prehm, Marko,Zeng, Xiangbing,Ungar, Goran,Tschierske, Carsten
supporting information; experimental part
p. 10599 - 10602
(2012/01/04)

Ti/Pd bimetallic systems for the efficient allylation of carbonyl compounds and homocoupling reactions
The allylation, crotylation and prenylation of aldehydes and ketones with stable and easily handled allylic carbonates is promoted by a Ti/Pd catalytic system. This Ti/Pd bimetallic system is especially convenient for the allylation of ketones, which are infrequent substrates in other related protocols, and can be carried out intramolecularly to yield five- and six-membered cyclic products with good stereoselectivities. In addition, Ti/Pd-mediated reductions and Wuertz-type dimerisation reactions can be readily carried out from allyl carbonates and carboxylates.
Millan, Alba,Campana, Araceli G.,Bazdi, Btissam,Miguel, Delia,Alvarez De Cienfuegos, Luis,Echavarren, Antonio M.,Cuerva, Juan M.
experimental part
p. 3985 - 3994
(2011/05/07)

Rhi-catalyzed two-component [(5+2)+1] cycloaddition approach toward [5-8-5] ring systems
Bringing it all together: [{Rh(CO)2Cl}2]-catalyzed two-component [(5+2)+1] cycloaddition of ene-vinylcyclopropanes with various tether types and substituents with CO has been designed for the one-pot synthesis of fused tricyclic cyclooctenones with atom and step economies.
Huang, Feng,Yao, Zhong-Ke,Wang, Yi,Wang, Yuanyuan,Zhang, Jialing,Yu, Zhi-Xiang
supporting information; experimental part
p. 1555 - 1559
(2011/08/05)

Palladium-catalyzed decarboxylative asymmetric allylic alkylation of enol carbonates
Palladium-catalyzed decarboxylative asymmetric allylic alkylation (DAAA) of allyl enol carbonates as a highly chemo-, regio-, and enantioselective process for the synthesis of ketones bearing either a quaternary or a tertiary R-stereogenic center has been investigated in detail. Chiral ligand L4 was found to be optimal in the DAAA of a broad scope of cyclic and acyclic ketones including simple aliphatic ketones with more than one enolizable proton. The allyl moiety of the carbonates has been extended to a variety of cyclic or acyclic disubstituted allyl groups. Our mechanistic studies reveal that, similar to the direct allylation of lithium enolates, the DAAA reaction proceeds through an "outer sphere" S N2 type of attack on the π-allylpalladium complex by the enolate. An important difference between the DAAA reaction and the direct allylation of lithium enolates is that in the DAAA reaction, the nucleophile and the electrophile were generated simultaneously. Since the π-allylpalladium cation must serve as the counterion for the enolate, the enolate probably exists as a tight-ion-pair. This largely prevents the common side reactions of enolates associated with the equilibrium between different enolates. The much milder reaction conditions as well as the much broader substrate scope also represent the advantages of the DAAA reaction over the direct allylation of preformed metal enolates.
Trost, Barry M.,Xu, Jiayi,Schmidt, Thomas
supporting information; experimental part
p. 18343 - 18357
(2010/04/25)

Mixed disproportionation versus radical trapping in titanocene(III)-promoted epoxide openings
The formation of either deoxygenation products or allylic alcohols from epoxides is observed when these substrates are treated with Cp2TiCl under anhydrous conditions. It seems that processes via trisubstituted radicals give allylic alcohols whereas processes via disubstituted radicals may give deoxygenation products or allylic alcohols depending on the structure of the original epoxide. This method allows a controlled access to these functional groups, providing a useful tool in organic synthesis. A mechanistic discussion for these transformations is reported.
Justicia, José,Jiménez, Tania,Morcillo, Sara P.,Cuerva, Juan M.,Oltra, J. Enrique
experimental part
p. 10837 - 10841
(2010/02/28)

The allyl intermediate in regioselective and enantioselective iridium-catalyzed asymmetric allylic substitution reactions
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Madrahimov, Sherzod T.,Markovic, Dean,Hartwig, John F.
supporting information; scheme or table
p. 7228 - 7229
(2009/10/17)

Palladium-catalyzed desulfinylative C-C allylation of Grignard reagents and enolates using allylsulfonyl chlorides and esters
2-Methylprop-2-ene-, prop-2-ene-, 1-methylprop-2-ene-, and (E)-but-2-enesulfonyl chlorides have been used as electrophilic partners in desulfinylative palladium-catalyzed C-C coupling with Grignard reagents and sodium salts of dimethyl malonate and methyl
Rao Volla, Chandra M.,Dubbaka, Srinivas Reddy,Vogel, Pierre
experimental part
p. 504 - 511
(2009/04/07)

Allylic alkylation and ring-closing metathesis in sequence: A successful cohabitation of Pd and Ru
An allylic alkylation/ring-closing metathesis domino catalytic process, wherein a palladium and a ruthenium catalyst are concomitantly present in the reaction mixture from the outset of the reaction, is developed. Evidence for Grubbs' catalysts activity in allylic alkylation is also reported.
Kammerer, Claire,Prestat, Guillaume,Gaillard, Thomas,Madec, David,Poli, Giovanni
p. 405 - 408
(2008/09/19)

Copper catalyzed enantioselective intramolecular aminooxygenation of alkenes
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Fuller, Peter H.,Kim, Jin-Woo,Chemler, Sherry R.
supporting information; experimental part
p. 17638 - 17639
(2009/06/25)

Counterintuitive kinetics in Tsuji-Trost allylation: Ion-pair partitioning and implications for asymmetric catalysis
The kinetics of Pd-catalyzed Tsuji-Trost allylation employing simple phosphine ligands (L = Ar3P, etc.) are consistent with turnover-limiting nucleophilic attack of an electrophilic [L2Pd(allyl)]+ catalytic intermediate. Counter-intuitively, when L is made more electron donating, which renders [L2Pd(allyl)]+ less electrophilic (by up to an order of magnitude), higher rates of turnover are observed. In the presence of catalytic NaBArF, large rate differentials arise by attenuation of ion-pair return (via generation of [L2Pd(allyl)]+ [BArF]-) a process that also increases the asymmetric induction from 28 to 78% ee in an archetypal asymmetric allylation employing BINAP (L*) as ligand. There is substantial potential for analogous application of [M]n+([BArF]-)n cocatalysis in other transition metal catalyzed processes involving an ionic reactant or reagent and an ionogenic catalytic cycle. Copyright
Evans, Louise A.,Fey, Natalie,Harvey, Jeremy N.,Hose, David,Lloyd-Jones, Guy C.,Murray, Paul,Orpen, A. Guy,Osborne, Robert,Owen-Smith, Gareth J. J.,Purdie, Mark
supporting information; experimental part
p. 14471 - 14473
(2009/02/08)

Allylic alkylation and amination using mixed (NHC)(phosphine) palladium complexes under biphasic conditions
A dramatic improvement of the catalytic activity was observed when a phosphine was added in allylic alkylation reactions catalyzed by (NHC)Pd(η3-C3H5)Cl complexes. Consequently, several palladium complexes, generated in situ from different NHC-silver complexes, [Pd(η3-C3H5)Cl]2 and PPh3, were tested in this reaction to evaluate their potential. High reaction rates and conversions could be obtained with this catalytic system in the alkylation of allylic acetates with dimethylmalonate, particularly under biphasic conditions using water/dichloromethane and KOH 1 M as the base. These conditions are experimentally more convenient and gave higher reaction rates than the classical anhydrous conditions (NaH/THF). In this system, the phosphine is essential since no conversion was obtained when it is not present. The steric hindrance of the carbene ligand has a great influence on the activity and the stability of the catalytic system. The best NHC ligands for this reaction are either 1-mesityl-3-methyl-imidazol-2-ylidene or 1-(2,6-diisopropylphenyl)-3-methyl-imidazol-2-ylidene which are less bulky among the NHC tested. These two ligands led in 5 min to a complete conversion at 20 °C. The Pd-catalyzed allylic amination reaction using (E)-1,3-diphenylprop-3-en-yl acetate and benzylamine was also tested with (NHC)(PPh3)Pd complexes and under the biphasic conditions. This reaction was found to be slower than the alkylation with dimethylmalonate but a complete conversion could be reached in 6 h at 20 °C using K2CO3 1 M as the base. NMR experiments indicated that mixed (NHC)(PPh3)Pd complexes are formed in situ but their structure could not be established exactly.
Flahaut, Alexandre,Roland, Sylvain,Mangeney, Pierre
p. 5754 - 5762
(2008/03/13)

Gold(I)-catalyzed [2 + 2]-cycloaddition of allenenes
A cationic phosphinegold(I)-catalyzed intramolecular [2 + 2]-cycloaddition between an allene and an alkene to form alkylidene?cyclobutanes is described. Additionally, the reported cycloisomerization reaction provides access to enantioenriched bicyclo-[3.2.0] structures using chiral biarylphosphinegold(I) complexes as catalysts. Copyright
Luzung, Michael R.,Mauleon, Pablo,Toste, F. Dean
p. 12402 - 12403
(2008/09/17)

Unprecedented hydrogen transfer from water to alkenes and alkynes mediated by TiIII and late transition metals
We describe how alkenes and alkynes can be hydrogenated under mild conditions by hydrogen transfer from water mediated by titanocene(III) and a substoichiometric quantity of one of the late transition metals usually employed as hydrogenation catalysts. This process proceeds presumably by H-atom transfer from TiIII-coordinated water to the late transition metal partner (depicted in the drawing above), a mechanism in support of which we provide theoretical and experimental evidence.
Campana, Araceli G.,Estevez, Rosa E.,Fuentes, Noelia,Rubles, Rafael,Cuerva, Juan M.,Bunuel, Elena,Cardenas, Diego,Oltra, J. Enrique
p. 2195 - 2198
(2008/02/04)

Synthesis of supercritical carbon dioxide soluble perfluorinated dendrons for surface modification
(Chemical Equation Presented) The rational design, synthesis, and characterization of a series of novel perfluorinated dendrons 14a,b, 25a,b, 26a,b, and 18 are described. The dendrimers were designed to have a thiol at the focal point for attachment to a gold surface to enable the fabrication of self-assembled monolayers (SAMs). Perfluorinated tails were attached to the periphery to provide solubility in supercritical carbon dioxide, and to increase the hydrophobicity and the stability of self-assembled monolayers formed. Mitsunobu reactions were utilized to provide high-yielding steps allowing large-scale production of the novel dendrimers.
Luscombe, Christine K.,Proemmel, Steffen,Huck, Wilhelm T. S.,Holmes, Andrew B.,Fukushima, Hitoshi
p. 5505 - 5513
(2008/02/09)

PdII-catalyzed aerobic allylic oxidative carbocyclization of allene-substituted olefins: Immobilization of an oxygen-activating catalyst
(Chemical Equation Presented) A good couple: Highly selective aerobic allylic oxidation with C-C bond formation is achieved by the use of coupled palladium and iron catalysis (see scheme; FePc = iron phthalocyanine). The use of an oxygen-activating catalyst is necessary for an efficient electron transfer from Pd0 to O2. The utility of this method is enhanced by the immobilization of the iron catalyst onto a resin.
Piera, Julio,Naerhi, Katja,Baeckvall, Jan-E.
p. 6914 - 6917
(2008/01/27)

A highly regioselective salt-free iron-catalyzed allylic alkylation
(Chemical Equation Presented) Ironing out the kinks: A highly regioselective allylic alkylation can be performed in the presence of catalytic amounts of an iron(-II) complex and triphenylphosphane (see scheme; EWG = electron-withdrawing group). Allyl carbonates and pronucleophiles are coupled in high yields with a high regioselectivity comparable only with that obtained with Rh catalysts. The reaction is broadly applicable and does not require external base.
Plietker, Bernd
p. 1469 - 1473
(2007/10/03)