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Catalytic Asymmetric Additions of Enol Silanes to In Situ Generated Cyclic, Aliphatic N-Acyliminium Ions
Strong and confined imidodiphosphorimidate (IDPi) catalysts enable highly enantioselective substitutions of cyclic, aliphatic hemiaminal ethers with enol silanes. 2-Substituted pyrrolidines, piperidines, and azepanes are obtained with high enantioselectiv
Aukland, Miles H.,Grossmann, Oleg,Lee, Sunggi,List, Benjamin,Maji, Rajat
supporting information

(2022/01/19)

Direct Hydrodecarboxylation of Aliphatic Carboxylic Acids: Metal- and Light-Free
A mild and inexpensive method for direct hydrodecarboxylation of aliphatic carboxylic acids has been developed. The reaction does not require metals, light, or catalysts, rendering the protocol operationally simple, easy to scale, and more sustainable. Crucially, no additional H atom source is required in most cases, while a broad substrate scope and functional group tolerance are observed.
Burns, David J.,Lee, Ai-Lan,McLean, Euan B.,Mooney, David T.
supporting information
p. 686 - 691
(2022/01/28)

Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
supporting information
p. 8413 - 8418
(2021/11/01)

Oxidations of pyrrolidines and piperidines to afford CH-functionalized isopropyl-1-carboxylate congeners
This article describes the action of iodine(III) reagents [diacetoxyiodobenzene, PhI(OAc)2, and iodosobenzene, (PhIO)n] in conjunction with TMSBr which act as functional bromine equivalents in unique oxidations of saturated, carbamate protected N-heterocycles. Interestingly, during this work, treatment of the same carbamates with molecular bromine alone afforded similar products, which were sequestered by the solvent methanol.
Gunawan, Steven,Bedard, Nathan,Foley, Christopher,Hulme, Christopher
supporting information

(2021/04/02)

Sustainable Route Toward N-Boc Amines: AuCl3/CuI-Catalyzed N-tert-butyloxycarbonylation of Amines at Room Temperature
N-tert-butoxycarbonyl (N-Boc) amines are useful intermediates in synthetic/medicinal chemistry. Traditionally, they are prepared via an indirect phosgene route with poor atom economy. Herein, a step- and atom-economic synthesis of N-Boc amines from amines, t-butanol, and CO was reported at room temperature. Notably, this N-tert-butyloxycarbonylation procedure utilized ready-made substrates, commercially available AuCl3/CuI as catalysts, and O2 from air as the sole oxidant. This catalytic system provided unique selectivity for N-Boc amines in good yields. More significantly, gram-scale preparation of medicinally important N-Boc amine intermediates was successfully implement, which demonstrated a potential application prospect in industrial syntheses. Furthermore, this approach also showed good compatibility with tertiary and other useful alcohols. Investigations of the mechanisms revealed that gold catalyzed the reaction and copper acted as electron transfer mediator in the catalytic cycle.
Cao, Yanwei,He, Lin,Huang, Yang
(2021/12/22)

Catalyst-Free Decarboxylation of Carboxylic Acids and Deoxygenation of Alcohols by Electro-Induced Radical Formation
Electro-induced reduction of redox active esters and N-phthalimidoyl oxalates derived from naturally abundant carboxylic acids and alcohols provides a sustainable and inexpensive approach to radical formation via undivided electrochemical cells. The resulting radicals are trapped by an electron-poor olefin or hydrogen atom source to furnish the Giese reaction or reductive decarboxylation products, respectively. A broad range of carboxylic acid (1°, 2°, and 3°) and alcohol (2° and 3°) derivatives are applicable in this catalyst-free reaction, which tolerated a diverse range of functional groups. This method features simple operation, is a sustainable platform, and has broad application.
Chen, Xiaoping,Luo, Xiaosheng,Peng, Xiao,Guo, Jiaojiao,Zai, Jiantao,Wang, Ping
p. 3226 - 3230
(2020/02/27)

Hydrogenation reaction method
The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0189-0192

(2020/05/14)

Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton-Coupled Electron Transfer
We report a catalytic, light-driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible-light irradiation in the presence of an IrIII-based photoredox catalyst, a Br?nsted base catalyst, and a hydrogen-atom transfer (HAT) co-catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O?H bonds through a proton-coupled electron-transfer mechanism. This method exhibits a broad substrate scope and high functional-group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented.
Knowles, Robert R.,Metrano, Anthony J.,Tsuchiya, Yuto,Tsui, Elaine
p. 11845 - 11849
(2020/05/22)

Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
supporting information
p. 4119 - 4129
(2020/08/10)

Synthesis of Amide Enol Carbamates and Carbonates through Cu(OTf)2-Catalyzed Reactions of Ynamides with t-Butyl Carbamates/Carbonates
A highly regioselective approach to access amide enol carbamates and carbonates 5a-5c′, 7a-7h, and 9 was developed through Cu(OTf)2-catalyzed reactions of ynamides 4 with t-butyl carbamates 2 and 8 and t-butyl carbonates 6. Moreover, this strategy was successfully applied to generate amide enol carbamates 11a-11s and 14a-14f from imides 10 and 13 with ynamides through an N-Boc cleavage-addition ring-opening process. A range of substituents was amenable to this transformation, and the desired amide enol carbamates and carbonates were obtained in moderate to good yields.
Han, Pan,Mao, Zhuo-Ya,Li, Ming,Si, Chang-Mei,Wei, Bang-Guo,Lin, Guo-Qiang
p. 4740 - 4752
(2020/04/30)

Dehydroxymethylation of alcohols enabled by cerium photocatalysis
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information
p. 10556 - 10564
(2019/08/20)

Dehydroxymethylation of Alcohols Enabled by Cerium Photocatalysis
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information
p. 10556 - 10564
(2019/08/28)

Catalytic protodeboronation of pinacol boronic esters: Formal anti-Markovnikov hydromethylation of alkenes
Pinacol boronic esters are highly valuable building blocks in organic synthesis. In contrast to the many protocols available on the functionalizing deboronation of alkyl boronic esters, protodeboronation is not well developed. Herein we report catalytic protodeboronation of 1°, 2° and 3° alkyl boronic esters utilizing a radical approach. Paired with a Matteson-CH2-homologation, our protocol allows for formal anti-Markovnikov alkene hydromethylation, a valuable but unknown transformation. The hydromethylation sequence was applied to methoxy protected (-)-Δ8-THC and cholesterol. The protodeboronation was further used in the formal total synthesis of δ-(R)-coniceine and indolizidine 209B.
Clausen, Florian,Kischkewitz, Marvin,Bergander, Klaus,Studer, Armido
p. 6210 - 6214
(2019/06/27)

Dual Benzophenone/Copper-Photocatalyzed Giese-Type Alkylation of C(sp3)?H Bonds
Photocatalyzed Giese-type alkylations of C(sp3)?H bonds are very attractive reactions in the context of atom-economy in C?C bond formation. The main limitation of such reactions is that when using highly polymerizable olefin acceptors, such as unsubstituted acrylates, acrylonitrile, or methyl vinyl ketone, radical polymerization often becomes the dominant or exclusive reaction pathway. Herein, we report that the polymerization of such olefins is strongly limited or suppressed when combining the photocatalytic activity of benzophenone (BP) with a catalytic amount of Cu(OAc)2. Under mild and operationally simple conditions, the Giese adducts resulting from the C(sp3)?H functionalization of amines, alcohols, ethers, and cycloalkanes could be synthesized. Preliminary mechanistic studies have revealed that the reaction does not proceed through a radical chain, but through a dual BP/Cu photocatalytic process, in which both CuII and low-valent CuI/0 species, generated in situ by reduction by the BP ketyl radical, may react with α-keto or α-cyano intermediate radicals, thus preventing polymerization.
Abadie, Baptiste,Jardel, Damien,Pozzi, Gianluca,Toullec, Patrick,Vincent, Jean-Marc
supporting information
p. 16120 - 16127
(2019/11/26)

Direct α-Monofluoroalkenylation of Heteroatomic Alkanes via a Combination of Photoredox Catalysis and Hydrogen-Atom-Transfer Catalysis
In this study, a new C(sp3)-H monofluoroalkenylation reaction involving cooperative visible-light photoredox catalysis and hydrogen-atom-transfer catalysis to afford products generated by selective hydrogen abstraction and radical-radical cross-coupling was described. This mild, efficient reaction shows high regioselectivity for the α-carbon atoms of amines, ethers, and thioethers and thus allows the preparation of monofluoroalkenes bearing various substituents. The reaction was applied to two bioactive molecules, indicating its utility for late-stage monofluoroalkenylation of compounds with inert C(sp3)-H bonds.
Tian, Hao,Xia, Qing,Wang, Qiang,Dong, Jianyang,Liu, Yuxiu,Wang, Qingmin
supporting information
p. 4585 - 4589
(2019/06/17)

Preparing technology of chiral N-BOC-pyrrolidine-2-boric acid
The invention discloses a preparing technology of chiral N-BOC-pyrrolidine-2-boric acid, and belongs to the field of agent intermediate synthesis. N-BOC-pyrrolidine and sec-butyllithium are subjectedto proton abstraction at low temperature, halogen boron agent is added, after a reaction is completed, saturated ammonium chloride is added to conduct cancellation, after evaporation to dryness of anorganic layer, mandelic acid and ethyl acetate are added, and after salt resolution, acidic hydrolysis is conducted to obtain chiral N-BOC-pyrrolidine-2-boric acid. By means of the method, the operating steps are short, raw materials are easily recycled, products with two structures can be obtained simply by changing the structure of a resolving agent, and the preparing technology has potential practical value.
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Paragraph 0017

(2018/07/03)

Photoredox-Mediated Direct Cross-Dehydrogenative Coupling of Heteroarenes and Amines
A photoredox-mediated direct cross-dehydrogenative coupling reaction to accomplish α-aminoalkylation of N-heteroarenes is reported. This mild reaction has a broad substrate scope, offers the first general method for synthesis of aminoalkylated N-heteroarenes without the need for substrate prefunctionalization, and is scalable to the gram level. Furthermore, the reaction was found to be applicable to other hydrogen donors besides amines (i.e., ethers, an aldehyde, a formamide, p-xylene, and alkanes), thus enabling the preparation of N-heteroarenes bearing various types of substituents.
Dong, Jianyang,Xia, Qing,Lv, Xueli,Yan, Changcun,Song, Hongjian,Liu, Yuxiu,Wang, Qingmin
supporting information
p. 5661 - 5665
(2018/09/21)

Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
Taylor, Nicholas J.,Emer, Enrico,Preshlock, Sean,Schedler, Michael,Tredwell, Matthew,Verhoog, Stefan,Mercier, Joel,Genicot, Christophe,Gouverneur, Véronique
supporting information
p. 8267 - 8276
(2017/06/27)

Copper nanoparticles catalyzed N-H functionalization: An efficient solvent-free N-tert-butyloxycarbonylation strategy
A chemoselective transformation of amines to their tert-butyloxycarbonyl (Boc) protected derivatives (NBoc) is described using Cu-NPs under solvent-free conditions. Simple method, rapid reaction rate, mild conditions, tolerance of a wide range of functional groups, excellent yield, ease recovery and high catalytic turnover are the salient features of this approach. tert-Butyloxycarbonylation of chiral amino acid esters and amino alcohols were performed without racemization.
Deb, Barnali,Debnath, Sudipto,Deb, Anindita,Maiti, Dilip K.,Majumdar, Swapan
supporting information
p. 629 - 633
(2017/01/25)

Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor
There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C-C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric acid is the sole byproduct. Mechanistic experiments suggest that this reaction is made possible by a hydrogen atom transfer from water that generates a Pd-hydride intermediate. Importantly, complete deuterium incorporation from stoichiometric D2O has also been achieved.
Cummings, Steven P.,Le, Thanh-Ngoc,Fernandez, Gilberto E.,Quiambao, Lorenzo G.,Stokes, Benjamin J.
supporting information
p. 6107 - 6110
(2016/06/09)

CHEMICAL BLOWING AGENT AND THERMALLY EXPANDABLE THERMOPLASTIC COMPOSITION
The present invention relates to a chemical blowing agent comprising at least one tertiary alkyl carbamate. The chemical blowing agent can be activated thermally and is suitable for foaming thermoplastic materials and can for example be incorporated into thermally expandable baffle and/or reinforcement elements which are used in automotive manufacturing and building insulation.
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Page/Page column 27; 28; 29

(2016/07/05)

Efficient N-Boc protection of amines by a reusable heterogeneous solid acid nanocatalyst at room temperature
An efficient and rapid protocol for chemoselective N-Boc protection of various structurally different aryl, aliphatic, and heterocyclic amines is reported with (Boc)2O using mesoporous silica phenylsulfonic acid (SBA-15-Ph-SO3H) as a recyclable and heterogeneous solid acid nanocatalyst under solvent-free condition at ambient temperature. The catalyst can be easily recovered and reused for ten reaction cycles for protection of amines without considerable loss of activity. The advantages of this green method are simplicity, easy workup, chemoselectivity, short reaction time, and excellent yield.
Veisi, Hojat,Sedrpoushan, Alireza,Ghazizadeh, Habibollah,Hemmati, Saba
p. 1451 - 1461
(2016/04/26)

Iron- and cobalt-catalyzed arylation of azetidines, pyrrolidines, and piperidines with grignard reagents
Iron- and cobalt-catalyzed cross-couplings between iodo-azetidines, -pyrrolidines, -piperidines, and Grignard reagents are disclosed. The reaction is efficient, cheap, chemoselective and tolerates a large variety of (hetero)aryl Grignard reagents.
Barr, Baptiste,Gonnard, Laurine,Campagne, Rmy,Reymond, Sbastien,Marin, Julien,Ciapetti, Paola,Brellier, Marie,Gurinot, Amandine,Cossy, Janine
supporting information
p. 6160 - 6163
(2015/01/16)

Design, synthesis, antiviral activity, and structure-activity relationships (SARs) of two types of structurally novel phenanthroindo/quinolizidine analogues
To investigate the influence of the variation of the original skeletons of natural phenanthroindo/quinolizidine alkaloids on antiviral activities, two types of structurally totally novel analogues 7a, 7b, 16a, and 16b were designed, synthesized, and evaluated against tobacco mosaic virus (TMV) for the first time. Bioassay results indicated that all four of the newly designed analogues showed good to excellent antiviral activities, among which analogue 16a dispalyed comparable activity with that of ningnanmycin, perhaps one of the most successful commercial antiviral agents, thus emerging as a potential inhibitor of plant virus and serving as a new lead for further optimization. Further structure-activity relationships are also discussed, demonstrating for the first time that the same changes of the original skeletons of phenanthroindolizidine and phenanthroquinolizidine exihibted totally different antiviral activities results, providing some original and useful information about the preferential conformation for maintaining high activities.
Su, Bo,Chen, Fazhong,Wang, Lizhong,Wang, Qingmin
p. 1233 - 1239
(2014/03/21)

A mild and green method for the N-BOC protection of amines without assistant of catalyst under solvent-free conditions
A facile, green and versatile method for the Boc protection of amines has been developed by a treatment with (Boc)2O without any additive at room temperature. The method is general for the preparation of N-Boc derivatives of aliphatic (acyclic and cyclic), aromatic, and heteroaromatic amines; primary and secondary amines. The advantages of this method are green, simplicity, short reaction times and excellent yields.
Mojtahedi, Mohammad Majid,Niknejad, Nina,Veisi, Hojat
p. 121 - 125
(2013/07/26)

Synthesis, X-ray crystallography, and reactions of N-acyl and N-carbamoyl succinimides
A collection of N-acyl and N-carbamoyl succinimides were prepared by acylation of succinimide with acyl chlorides or by ethylene dichloride (EDC) coupling of carboxylic acids. The x-ray crystal structures of N-benzoyl and N-p-nitrobenzoyl succinimides were determined. The N-acyl succinimides were effective in acylating primary amines, a secondary amine, and an aromatic amine. Copyright
Goodman, Cassie A.,Eagles, Joel B.,Rudahindwa, Leandre,Hamaker, Christopher G.,Hitchcock, Shawn R.
p. 2155 - 2164
(2013/07/25)

HETEROCYCLIC COMPOUNDS AND METHODS FOR THEIR USE
The present invention relates to heterocyclic compounds useful for antagonising angiotensin II Type 2 (AT2) receptor. More particularly the invention relates to pyrrolidine and azetidine compounds, compositions containing them and their use in methods of treating or preventing disorders or diseases associated with AT2 receptor function including neuropathic pain, inflammatory pain, conditions associated with neuronal hypersensitivity, impaired nerve conduction velocity, cell proliferation disorders, disorders associated with an imbalance between bone resorption and bone formation and disorders associated with aberrant nerve regeneration.
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Page/Page column 94; 95

(2013/07/19)

Asymmetric lithiation trapping of N -boc heterocycles at temperatures above -78°C
The asymmetric lithiation trapping of N-Boc heterocycles using s-BuLi/chiral diamines at temperatures up to -20°C is reported. Depending on the N-Boc heterocycle, lithiation is accomplished using s-BuLi and (-)-sparteine or the (+)-sparteine surrogate in the temperature range -50 to -20°C for short reaction times (2-20 min). Subsequent electrophilic trapping or transmetalation-Negishi coupling delivered functionalized N-Boc heterocycles in 47-95% yield and 77:23-93:7 er. With N-Boc pyrrolidine, trapped products can be generated in ～90:10 er even at -20°C.
Gelardi, Giacomo,Barker, Graeme,O'Brien, Peter,Blakemore, David C.
supporting information
p. 5424 - 5427
(2013/11/19)

Total synthesis of hygrolines and pseudohygrolines
A concise two-step synthesis of all four diastereoisomeric hygrolines ((-)-hygroline (1), (+)-hygroline (2), (-)-pseudohygroline (3), (+)-pseudohygroline (4)) has been developed based on the (-)-sparteine (5)- or (+)-sparteine surrogate 11-mediated enantioselective lithiation of N-Boc pyrrolidine (6), followed by reaction of the chiral anion with (S)- or (R)-propylene oxide. Reduction of the resulting N-Boc amino alcohols furnished hygrolines and pseudohygrolines in 30% to 56% overall yields with dr's > 95:5.
Liniger, Marc,Estermann, Katja,Altmann, Karl-Heinz
p. 11066 - 11070
(2013/11/19)

RADIATION-SENSITIVE RESIN COMPOSITION, METHOD FOR FORMING A RESIST PATTERN, COMPOUND, AND POLYMER
A radiation-sensitive resin composition includes a first polymer that includes a repeating unit having an acid-labile group and becomes alkali-soluble upon dissociation of the acid-labile group, and a radiation-sensitive acid-generating agent. The acid-labile group has a structure shown by a general formula (1). R1 represents a methyl group or the like, R2 represents a hydrocarbon group that forms a cyclic structure, R3 represents a fluorine atom or the like, R4 represents a carbon atom, and n1 is an integer from 1 to 7.
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(2012/06/30)

Microwave assisted mild, rapid, solvent-less, and catalyst-free chemoselective N-tert-butyloxycarbonylation of amines
Microwave assisted simple, rapid, solventless, and catalyst-free chemoselective method for the protection of amino group in aromatic, aliphatic, heterocyclic, aralkyl amines, phenyl hydrazine, and amino acid esters in good to excellent isolated yield (83-98%) in short reaction time (2-12 min) has been reported.
Dighe, Satish N.,Jadhav, Hemant R.
p. 5803 - 5806
(2012/10/29)

Development of an asymmetric trimethylenemethane cycloaddition reaction: Application in the enantioselective synthesis of highly substituted carbocycles
A protocol for the enantioselective [3+2] cycloaddition of trimethylenemethane (TMM) with electron-deficient olefins has been developed. The synthesis of novel phosphoramidite ligands was critical in this effort, and the preparation and reactivity of these ligands is detailed. The evolution of the ligand design, commencing with acyclic amine-derived phosphoramidites and leading to cyclic pyrrolidine and azetidine structures, is discussed. The conditions developed to effect an asymmetric TMM reaction using 2-trimethylsilylmethyl allyl acetate were shown to be tolerant of a wide variety of alkene acceptors, providing the desired methylenecyclopentanes with high levels of enantioselectivity. The donor scope was also explored, and substituted systems were tolerated, including one bearing a nitrile moiety. These donors were reactive with unsaturated acylpyrroles, giving the product cyclopentane rings bearing three stereocenters in high enantioselectivity and complete diastereoselectivity.
Trost, Barry M.,Silverman, Steven M.,Stambuli, James P.
scheme or table
p. 19483 - 19497
(2012/01/06)

Asymmetric deprotonation using s -BuLi or i -PrLi and chiral diamines in THF: The diamine matters
The solution structures of [6Li]-i-PrLi complexed to (-)-sparteine and the (+)-sparteine surrogate in Et2O-d10 and THF-d8 at -80 °C have been determined using 6Li and 13C NMR spectroscopy. In Et2O, i-PrLi/(-)-sparteine is a solvent-complexed heterodimer, whereas i-PrLi/(+)-sparteine surrogate is a head-to-tail homodimer. In THF, there was no complexation of (-)-sparteine to i-PrLi until ≥3.0 equiv (-)-sparteine and with 6.0 equiv (-)-sparteine, a monomer was characterized. In contrast, the (+)-sparteine surrogate readily complexed to i-PrLi in THF, and with 1.0 equiv (+)-sparteine surrogate, complete formation of a monomer was observed. The NMR spectroscopic study suggested that it should be possible to carry out highly enantioselective asymmetric deprotonation reactions using i-PrLi or s-BuLi/(+)-sparteine surrogate in THF. Hence, three different asymmetric deprotonation reactions (lithiation-trapping of N-Boc pyrrolidine, an O-alkyl carbamate, and a phosphine borane) were investigated; it was shown that reactions with (-)-sparteine in THF proceeded with low enantioselectivity, whereas the corresponding reactions with the (+)-sparteine surrogate occurred with high enantioselectivity. These are the first examples of highly enantioselective asymmetric deprotonation reactions using organolithium/diamine complexes in THF.
Carbone, Giorgio,O'Brien, Peter,Hilmersson, Goeran
supporting information; experimental part
p. 15445 - 15450
(2011/01/06)

An expeditious, efficient green methodology for the Boc protection of amines and silyl protection of alcohols over tungstophosphoric acid-doped mesoporous silica
An efficient, chemoselective and eco-friendly protocol for the protection of amines as N-tert-butylcarbamate using (Boc)2O and protection of alcohols as silyl ether using HMDS over tungstophosphoric acid/SBA15 has been developed. Solventless condition, easy work-up, short reaction time, excellent yields and reusability of the catalyst are the striking features of this methodology which can be considered to be one of the better methods for the protection of amines and alcohols.
Karmakar, Bikash,Banerji, Julie
experimental part
p. 3855 - 3858
(2010/08/20)

Diamine-free lithiation-trapping of N-Boc heterocycles using s-BuLi in THF
A diamine-free protocol for the s-BuLi-mediated lithiation-trapping of N-Boc heterocycles has been developed. In the optimized procedure, lithiation is accomplished using s-BuLi in THF at -30 °C for only 5 or 10 min. Subsequent electrophilic trapping or transmetalation-Negishi coupling delivered a range of functionalized pyrrolidines, imidazolidines, and piperazines in 43-83% yield.
Barker, Graeme,Obrien, Peter,Campos, Kevin R.
supporting information; experimental part
p. 4176 - 4179
(2010/11/16)

Thioglycoluril as a highly efficient, recyclable and novel organocatalyst for N-Boc protection of amines
A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using thioglycoluril as the catalyst is described. The catalyst can be readily separated from the reaction products by simple filtration and recovered for reuse. No competitive side reactions, such as formation of isocyanate, urea, oxazolidinone, and N,N-di-Boc derivatives were observed.
Khaksar, Samad,Vahdat, Seyed Mohammad,Tajbakhsh, Mahmood,Jahani, Fatemeh,Heydari, Akbar
experimental part
p. 6388 - 6391
(2011/01/03)

Amberlyst-15: a mild, efficient and reusable heterogeneous catalyst for N-tert-butoxycarbonylation of amines
A mild and versatile method has been developed for the chemoselective N-tert-butoxycarbonylation of amines in the presence of Amberlyst-15 under solvent-free condition. The method is general for the preparation of N-Boc derivatives of aliphatic (acyclic and cyclic) and aromatic amines.
Kumar, K. Shiva,Iqbal, Javed,Pal, Manojit
experimental part
p. 6244 - 6246
(2010/01/11)

An efficient and chemoselective Br?nsted acidic ionic liquid-catalyzed N-Boc protection of amines
The first report of a Br?nsted acidic ionic liquid, 1-methylimidazolium tetrafluoroborate [(HMIm)BF4], catalyzed efficient and chemoselective N-Boc protection of various amines using (Boc)2O is presented. Optically pure amino alcohols and amino acid esters were converted efficiently to their corresponding optically pure N-Boc derivatives. The reported method is mild, solvent-free and has the advantages of both homogeneous and heterogeneous catalysis with high product yields, selectivity and ease of product separation.
Sunitha, Sadula,Kanjilal, Sanjit,Reddy, P. Srinivasa,Prasad, Rachapudi B.N.
p. 2527 - 2532
(2008/09/19)

A mild Boc deprotection and the importance of a free carboxylate
We report a facile and rapid removal of Boc protecting groups using microwave heating in H2O, with deprotection only requiring a free carboxylic acid group in the starting material. Unlike previous approaches, no additional reagents are required.
Thaqi, Ali,McCluskey, Adam,Scott, Janet L.
supporting information; experimental part
p. 6962 - 6964
(2009/04/07)

Decarboxylative reduction of free aliphatic carboxylic acids by photogenerated cation radical
The decarboxylation of free carboxylic acids was effected by a photogenerated cation radical of phenanthrene to yield the reduction product in the presence of a thiol, which provides an alternative method to the Barton decarboxylation procedure for aliphatic acids such as N-Boc amino acids. The Royal Society of Chemistry.
Yoshimi, Yasuharu,Itou, Tatsuya,Hatanaka, Minoru
p. 5244 - 5246
(2008/09/19)

Efficient, solventless N-Boc protection of amines carried out at room temperature using sulfamic acid as recyclable catalyst
A simple, rapid, and efficient protocol for the chemoselective N-Boc protection of amines using sulfamic acid as catalyst is described. N-Boc protection of various structurally diverse aliphatic, aromatic, alicyclic, and heterocyclic amines (1°, 2°, 3°) was carried out with (Boc)2O using sulfamic acid as catalyst (5 mol %) at room temperature under solventless conditions. The advantages of this method are simplicity, shorter reaction times (1-15 min), a cost-effective catalyst, and excellent isolated yields (90-100%); it is also environmentally benign. Moreover, the combined use of ultrasound and sulfamic acid achieves a synergic effect that is especially marked in the N-Boc protection of deactivated (sterically hindered and electron-deficient) amines. The catalyst possesses distinct advantages: ease of handling, cleaner reactions, high activity, and excellent chemoselectivity.
Upadhyaya, Dharita J.,Barge, Alessandro,Stefania, Rachele,Cravotto, Giancarlo
p. 8318 - 8322
(2008/04/13)

Reactions of iminium ions with Michael acceptors through a Morita-Baylis-Hillman-type reaction: Enantiocontrol and applications in synthesis
(Chemical Equation Presented) All adducts one way: Iminium ions, generated in situ from the corresponding N,O-acetals, can be used as electrophiles in a Morita-Baylis-Hillman-type reaction with a wide range of Michael acceptors (enones, enals, S- and O-acrylates). The reaction has been rendered asymmetric using sulfide 1 (see scheme; DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene, TMSOTf=trimethylsilyl trifluoromethanesulfonate).
Myers, Eddie L.,De Vries, Johannes G.,Aggarwal, Varinder K.
p. 1893 - 1896
(2008/03/12)

Molecular iodine-catalyzed facile procedure for N-Boc protection of amines
An efficient and practical protocol for the protection of various structurally and electronically divergent aryl and aliphatic amines using (Boc)2O in the presence of a catalytic amount of molecular iodine (10 mol%) under solvent-free conditions at ambient temperature is presented.
Varala, Ravi,Nuvula, Sreelatha,Adapa, Srinivas R.
p. 8283 - 8286
(2007/10/03)

Catalyst-free chemoselective N-tert-butyloxycarbonylation of amines in water
Catalyst-free N-tert-butyloxycarbonylation of amines in water is reported. The N-t-Boc derivatives were formed chemoselectively without any isocyanate, urea, N,N-di-t-Boc, and O/S-t-Boc as side products. Chiral amines, esters of α-amino acids, and β-amino alcohol afforded optically pure N-t-Boc derivatives. Amino alcohol and 2-aminophenol afforded the N-t-Boc derivative without oxazolidinone formation. Selectivity was observed during competition of aromatic amine vs aliphatic amine, amine vs amino acid ester, amine vs amino alcohol, and primary amine vs secondary amine.
Chankeshwara, Sunay V.,Chakraborti, Asit K.
p. 3259 - 3262
(2007/10/03)

QUINAZOLINE DERIVATIVES AS INHIBITORS OF VEGF RECEPTOR TYROSINE KINASES
The present invention relates to compounds of the Formula (I): wherein Z is -NH-, -O- or -S-; R 1 represents bromo or chloro; R 3 represents C 1-3 alkoxy or hydrogen; R 2 is selected from one of the following three groups: (i) Q 1 X 1 - wherein X 1 and Q 1 are as defined herein; (ii) Q 15 W 3 - wherein Q 15 and W 3 are as defined herein; and (iii) Q 21 W 4 C 1-5 alkylX 1 wherein X 1 , W 4 and Q 21 are as defined herein; and salts thereof; their use in the manufacture of a medicament for use in the production of an antiangiogenic and/or vascular permeability reducing effect in warm blooded animals; processes for the preparation of such compounds; pharmaceutical compositions containing a compound of formula (I) or a pharmaceutically acceptable salt thereof and methods of treating disease states involving angiogenesis by administering a compound of formula (I) or a pharmaceutically acceptable salt thereof. The compounds of formula (I) inhibit the effects of VEGF, a property of value in the treatment of a number of disease states including cancer and rheumatoid arthritis.
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Page/Page column 66-67

(2010/02/10)

QUINAZOLINE DERIVATIVE AS ANGIOGENESIS INHIBITORS
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Page/Page column 82-83

(2010/02/10)

Cryoelectrochemistry: Electrochemical reduction of 2(RS)-methyl 1-(tert-butoxycarbonyl)-2-iodomethyl-2,5-dihydropyrrole-2-carboxylate
Cryoelectrochemisty with cyclic voltammetry and chronoamperometry has been applied to give an insight into a reductive pyrroline ring opening reaction, and has allowed the number of electrons participating in the reaction to be deduced from potential step experiments.
Banks, Craig E.,Evans, Russell G.,Rodrigues, Jason,Turner, Peter G.,Donohoe, Timothy J.,Compton, Richard G.
p. 2365 - 2372
(2007/10/03)

QUINAZOLINE DERIVATIVES AS SRC TYROSINE KINASE INHIBITORS
The invention concerns quinazoline derivatives of Formula (I): (A chemical formula should be inserted here - please see paper copy enclosed herewith) wherein Z is an O, S, SO, SO2, N(R2) or C(R2)2 group wherein each R2 group is hydrogen or (1-8C) alkyl, m is 0, 1, 2 or 3, each R1 group is selected from halogeno, (1-8C) alkyl, (1-6C) alkoxy and any of the other meanings defined in the description, n is 0, 1, 2 or 3, and each R3 group is selected from halogeno, (1-8C) alkyl, (1-6C) alkoxy and any of the other meanings defined in the description, or pharmaceutically-acceptable salts thereof, processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use as an anti-invasive agent in the containment and/or treatment of solid tumour disease.
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Page 76-77

(2008/06/13)

4-ANILINO QUINAZOLINE DERIVATIVES AS ANTIPROLIFERATIVE AGENTS
The invention concerns quinazoline derivatives of Formula (I) wherein each of Q1, Z, R1 and Q2 have any of the meanings defined in the description; processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use as an antiproliferative agent in the prevention or treatment of tumours which are sensitive to inhibition of erbB receptor tyrosine kinases.
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Page/Page column 148-149

(2010/02/07)

Stereoselective construction of X-azabicyclo[m.2.1]alkanes by [3+2]-cycloaddition of non-stabilized cyclic azomethine ylides: Synthesis of enantiopure constrained amino acids and formal total synthesis of optically active epibatidine
A new and general strategy for the stereoselective construction of X-azabicyclo[m.2.1]alkanes has been developed by the [3+2]-cycloaddition of cyclic azomethine ylides with suitable achiral dipolarophiles. The cyclic azomethine ylides, where the whole of the ylide conjugation is in the ring, have been generated by the sequential double desilylation of the N-alkyl-α,α′-bis(trimethylsilyl) cyclic amines utilizing Ag(I)F as one electron oxidant. The structural rigidity of cyclic azomethine ylides has allowed preferential facial discrimination by the dipolarophile resulting into very good exolendo selectivity. The exolendo selectivity associated with these cycloadditions has been further exploited to access optically pure X-azabicyclo[m.2.1]alkanes by carrying out the cycloadditions with the Oppolzer's acryloyl dipolarophile. Application of this methodology is demonstrated by the construction of few constrained amino acids related to azabicyclic structural framework and the formal total synthesis of optically active epibatidine.
Pandey, Ganesh,Laha, Joydev K,Lakshmaiah
p. 3525 - 3534
(2007/10/03)