- Merging Asymmetric [1,2]-Additions of Lithium Acetylides to Carbonyls with Type II Anion Relay Chemistry
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An enantioselective three-component coupling reaction has been developed, enabling the union of a variety of lithium acetylides and electrophiles exploiting an achiral linchpin via an anionic reaction cascade. This Type II Anion Relay Chemistry tactic is initiated via an enantioselective [1,2]-carbonyl addition exploiting BINOL catalysis to access an enantioenriched alkoxide intermediate. Migration of charge across the linchpin via a [1,4]-Brook rearrangement with electrophile capture affords a three-component propargyl ether adduct. Herein, we report the development, scope, and limitations of this reaction sequence.
- O'brien, Kevin T.,Smith, Amos B.
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- INDOLE CARBOXAMIDE COMPOUNDS AND USE THEREOF FOR THE TREATMENT OF MYCOBACTERIAL INFECTIONS
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Provided herein are compounds of Formula (I) as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of tuberculosis.
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Page/Page column 46; 47
(2021/04/02)
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- Phosphine-Catalyzed Intermolecular Annulations of Fluorinated ortho-Aminophenones with Alkynones – The Switchable [4+2] or [4+2]/[3+2] Cycloaddition
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A phosphine-catalyzed intermolecular annulation reaction of functionalized ortho-aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2-alkynylquinolines and benzo-fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. (Figure presented.).
- Zhang, Yanshun,Sun, Yaoliang,Wei, Yin,Shi, Min
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supporting information
p. 2129 - 2135
(2019/03/13)
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- Phosphane-Catalyzed [3+3] Annulation of C,N-Cyclic Azomethine Imines with Ynones: A Practical Method for Tricyclic Dinitrogen-Fused Heterocycles
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A phosphane-catalyzed [3+3] annulation of azomethine imines with ynones has been developed. Under mild reaction conditions, the reaction proceeds smoothly to afford tricyclic dinitrogen-fused heterocyclic compounds in moderate to excellent yields with moderate to excellent stereoselectivies. Using a chiral phosphine as the catalyst, the reaction could work to give the cycloadduct in moderate yield with moderate enantioselectivity. (Figure presented.) .
- Li, Zhen,Yu, Hao,Liu, Yang,Zhou, Leijie,Sun, Zhanhu,Guo, Hongchao
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supporting information
p. 1880 - 1885
(2016/07/06)
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- Aerobic oxidation of propargylic alcohols to αβ,-unsaturated alkynals or alkynones catalyzed by fe(NOH, TEMPO and sodium chloride in toluene
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A practical aerobic oxidation of propargylic alcohols using Fe(NOH, TEMPO and sodium chloride in toluene at room temperature was applied to various type of propargylic alcohols affording ,-unsaturated alkynals or alkynones in good to excellent yields. This protocol could be applied in academic laboratories as well as in industrial-scale production.
- Liu, Jinxian,Xie, Xi,Ma, Shengming
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experimental part
p. 1569 - 1576
(2012/06/30)
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- Ni(0) catalyzed one step synthesis of benzo[b][1,8] naphthyridin-5-ones from silyl-α-ketoalkynes in water
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One-step synthesis of new benzo[b][1,8]naphthyridin-5-ones using a Ni(0) catalytic system in aqueous medium with mild conditions of pressure and temperature is described. It is very interesting to note that Ni(0) catalyst increases the rate of condensation of several α-ketoalkynes with 2-amino-4(1H)-quinolinone obtaining benzo[b][1,8]naphthyridin-5-ones in very high yield. In the absence of catalyst this condensation reaction takes 24 h with a product yield of 10%.
- Suárez-Ortiz, Gloria Alejandra,Sharma, Pankaj,Amézquita-Valencia, Manuel,Arellano, Ivonne,Cabrera,Rosas, Noé
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scheme or table
p. 1641 - 1643
(2011/04/25)
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- Stereoselective One-Pot synthesis of 1-Aminoindanes and 5,6-Fused azacycles using a Gold-Catalyzed Redox-Pinacol-Mannich-Michael cascade
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"Chemical Equation Presented" Just another Mannich Monday: A cascade intramolecular redox-pinacol-Mannich-Michael reaction sequence catalyzed by gold complexes can be used to generate a variety of structures including spirocycles, 1-aminoindanes, and 5,6-fused azabicycles that have a quaternary carbon center. The reaction is characterized by complete atom-economy, high diastereoselectivity, and remarkable efficiency through tandem reactions.
- Yeom, Hyun-Suk,Lee, Youngun,Jeong, Jaewon,So, Eunsoo,Hwang, Soojin,Lee, Ji-Eun,Lee, Shim Sung,Shin, Seunghoon
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supporting information; experimental part
p. 1611 - 1614
(2010/06/15)
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- Improved method for the synthesis of β-carbonyl silyl-1,3-dithianes by the double conjugate addition of 1,3-dithiol to propargylic carbonyl compounds
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(Chemical Equation Presented) Base-mediated double conjugate addition of 1,3-propane dithiol to various silylated propargylic aldehydes and ketones allows for an efficient and scalable synthesis of β-carbonyl silyl-1,3-dithianes.
- Mukherjee, Sumit,Kontokosta, Dimitra,Patil, Aditi,Rallapalli, Sivakumar,Lee, Daesung
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supporting information; experimental part
p. 9206 - 9209
(2010/03/02)
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- Bronsted acid-promoted glycosylations of disaccharide glycal substructures of the saccharomicins
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An acid-promoted glycosylate and alkynol cycloisomerization sequence provided direct access to the 2-deoxytrisaccharide corresponding to the fucose-saccharosamine-digitoxose substructure of saccharomicin B. In the course of this work, the absolute stereochemistry of the repeating fucose- saccharosamine disaccharide of saccharomicins was also confirmed.
- Balthaser, Bradley R.,McDonald, Frank E.
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supporting information; experimental part
p. 4850 - 4853
(2009/12/28)
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- Regiospecific synthesis of 5-silyl azoles
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5-Silylisoxazoles bearing other silyl groups different to the more usual trimethylsilyl have been prepared by condensation of silylalkynones with hydroxylamine hydrochloride. The reaction with hydrazines is more complex and leads to 5-silylpyrazoles or the corresponding hydrazones, which can be cyclized by reaction with electrophiles. This has allowed us to synthesize 5-silylpyrazoles functionalized at C-4 by groups impossible to introduce by electrophilic substitution of the pyrazole nucleus.
- Cuadrado, Purificación,González-Nogal, Ana M,Valero, Raquel
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p. 4975 - 4980
(2007/10/03)
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- Carbon-carbon bond forming reactions by using bistrifluoromethanesulfonimide
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Bistrifluoromethanesulfonimide has been used to catalyze C-C bond forming reactions such as Friedel-Crafts, Mukaiyama, 1,2-addition and 1,4-addition as well as C-glycosidation reactions.
- Cossy,Lutz,Alauze,Meyer
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- Trimethylsilylethynyl ketones as surrogates for ethynyl ketones in the double Michael reaction
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Trimethylsilylethynyl ketones can be desilylated in the presence of a tethered carbon diacid and induced to undergo a double Michael reaction in situ. The trimethylsilylethynyl ketones can serve as surrogates of ethynyl ketones that are difficult to prepare or isolate.
- Holeman, Derrick S.,Rasne, Ravindra M.,Grossman, Robert B.
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p. 3149 - 3151
(2007/10/03)
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- C-C-bond formation in reactions of [(η5-C5H4SiMe3)2Ti(C?CR1)2]CuR with acyl chlorides and anhydrides
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The chemical behaviour of selected {[Ti](C?CR1)2}CuR complexes (1a: R1=SiMe3, R=CH3; 1b: R1=tBu, R=CH3; 1c: R1=tBu, R=C?CSiMe3) towards a number of different acyl chlorides and anhydrides is described. The reaction of 1a or 1b with R2C(O)Cl (2a: R2=CH3, 2b: R2=C6H5) produces the ketones R2C(O)R (4a: R=R2=CH3; 4b: R=CH3, R2=C6H5; 4c: R=C?CSiMe3, R2=CH3, 4d: R=C?CSiMe3, R2=C6H5) along with {[Ti](Cnequiv;CR1)2}CuCl (3a: R1=SiMe3, 3b: R1=tBu). However, on treatment of 1b or 1c with [CH3C(O)]2O (5a) the ketones 4a or 4c are formed along with the copper(I) acetate complex {[Ti](C?CtBu)2}CuOC(O)CH3 (6), while the reaction of 1b or 1c with CH3CO2H (5b) yields methane and 6. In addition, when 1b or 1c are reacted with maleic (7), phthalic (9a) or tetrachlorophthalic anhydride (9b) the copper(I) carboxylates {[Ti](C?CtBu)2}CuOC(O)-cis-CH=CH-C(O)R (8a: R=CH3, 8b: R=C?CSiMe3) and {[Ti](C?CtBu)2}CuOC(O)-C6H4-n Cln-2-C(O)R (10a: n=0, R=CH3; 10b: n=0, R=C?CSiMe3; 10c: n=4, R=C?CSiMe3) are produced, which upon addition of, e.g. HBr afford via cleavage of the copper-oxygen σ-bond {[Ti](C?CtBu)2}CuBr (3c) and the corresponding carboxylic acids cis-HO2C-CH=CH-C(O)CH3 (11a) or HO2C-C6H4-2-C(O)CH3 (11b), respectively.
- Frosch,Back,Lang
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p. 140 - 147
(2007/10/03)
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- Synthesis and pharmacological characterization of new analogs of broxaterol
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A series of isoxazole derivatives structurally related to broxaterol 1 has been prepared and tested for their potency to β1 and β2 adrenergic receptors. At variance with broxaterol, none of the tested compounds displayed agonistic activity. The 3-isopropenyl derivative 5f is the most potent antagonist both in the trachea and atria preparations.
- De Amici,Conti,Dallanoce,Kassi,Castellano,Stefancich,De Micheli
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- Asymmetric reduction of ethynyl ketones and ethynylketoesters by secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus
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Secondary alcohol dehydrogenase (SADH) from Thermoanaerobacter ethanolicus, an NADP-dependent, thermostable oxidoreductase, reduces ethynyl ketones and ethynylketoesters enantioselectively to the corresponding propargyl (propargyl = prop-2-ynyl) alcohols. Ethynyl ketones, in general, are reduced with moderate enantioselectivity (with the exception of 4-methylpent-l-yn-3-one, which gives the (S)-alcohol with >98% ee). Although ethynyl ketones bearing a small (up to n-propyl) alkyl substituent are reduced to (S)-alcohols, larger ethynyl ketones give (R)-alcohols. In contrast, ethynylketoesters are converted to (R)-ethynylhydroxyesters of excellent optical purity. Unexpectedly, isopropyl ethynylketoesters give higher chemical yields and higher enantioselectivities of ethynylhydroxyesters than methyl or ethyl ethynylketoesters. The optically pure ethynylhydroxyesters may serve as useful chiral building blocks for asymmetric synthesis.
- Heiss, Christian,Phillips, Robert S.
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p. 2821 - 2825
(2007/10/03)
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- Synthesis and reactivity of 2,4,4-trimethyl-2-silylethynyl substituted 1,3-dioxanes
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A synthesis was developed for 2,4,4-trimethyl-2-ethynyl substituted 1,3-dioxane. Hydrolysis and cleavage thereof at the Si-Csp bond was investigated.
- Kosulina,Ol'khovskaya,Kul'nevich
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p. 608 - 613
(2007/10/03)
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- Efficient large-scale synthesis of 4-phenyl-3-butyn-2-one, a key intermediate for a novel potent adenosine antagonist
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Phenylacetylenic Grignard reagent reacts with acetic anhydride under mild conditions to give 4-phenyl-3-butyn-2-one in high yield. This method was applicable to a large-scale synthesis, and optimized reaction conditions have been investigated.
- Zanka, Atsuhiko
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- A Pseudomonas sp. Alcohol Dehydrogenase with Broad Substrate Specificity and Unusual Stereospecificity for Organic Synthesis
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A new alcohol dehydrogenase from Pseudomonas sp. strian PED has been isolated and characterized.The enzyme exhibits a broad substrate specificity, accepting aromatic, cyclic, and aliphatic compounds as substrates.The Km values were determined as 525 μM for NAD and 75 μM for 2-propanol with a specific activity of 36 U/mg.The kinetic mechanism is ordered bi-bi with the cofactor binding first and releasing last.The enzyme transfers the pro-R hydride of NADH to the si face of carbonyl compounds to yield (R) alcohols.Synthetic-scale reductions of a number of representative compounds were carried out in high enentiomeric excess with in situ regeneration of NADH using 2-propanol as the hydride source and the same enzyme as catalyst.
- Bradshaw, Curt W.,Fu, Hong,Shen, Gwo-Jenn,Wong, Chi-Huey
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p. 1526 - 1532
(2007/10/02)
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- Carbonium Ion Rearrangements Controlled by the Presence of a Silyl Group
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γ-Silyl tertiary alcohols rearrange in protic acid with 1,2-shift of hydride, phenyl, or alkyl groups, and loss of the silyl group to give alkenes.The placing of the silyl group thus controls the carbonium ion rearrangement in a preparatively useful way.Methoxycarbonyl groups do not migrate; instead, cyclopropanes are formed, except when the conformation suitable for cyclopropane formation is unattainable.When the alkene product is 2,2-disubstituted, it can be reprotonated under the reaction conditions and does not therefore always survive.This can be avoided by carrying out the reaction using a Lewis acid on the silyl ether.The starting γ-silyl alcohols are prepared by a variety of versatile methods.
- Fleming, Ian,Patel, Shailesh K.,Urch, Christopher J.
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p. 115 - 124
(2007/10/02)
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- Efficient methods for the preparation of acetylenic ketones
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A number of acetylenic ketones RCCC(=O)R' have been obtained in good yields from lithiated acetylenes RCCLi and acetic anhydride, N,N-dimethylacetamide, or N,N-dimethylbenzamide.The most convenient and general method consists of treating alkynylzinc chlorides with acid halides R'C(=O)Cl.Benzoyl chloride (R'=Ph), acryloyl chloride (R'=CH2=CH) and butynoyl chloride (R'=C2H5CC) react only in the presence of a catalytic amount of Pd4.
- Verkruijsse, H. D.,Heus-Kloos, Y. A.,Brandsma, I.
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p. 289 - 294
(2007/10/02)
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- Phenyl Cations as Reactive Intermediates in the Solvolysis of Dien-in-yl Triflates
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The synthesis, separation, and solvolysis of the stereoisomeric 1,4-dimethyl-1,3-hexadien-5-yn-1-yl triflates 15a - c in various solvents are described.In contrast to the (Z)-isomers 15a - c, the (E)-isomers 15a - c react preferably via an intermediate phenyl cation 16 to give the phenyl ethers 17.Further mechanistic investigations which support the formation of the intermediate phenyl cations 16 are described.The formation of the benzylic derivatives 18 is discussed.
- Holweger, Walter,Hanack, Michael
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p. 3004 - 3020
(2007/10/02)
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- LITHIATED 2-ALKYNYL-1,3-DIOXANES AS FULLY OXYGENATED ACYL-ANION EQUIVALENTS: SYNTHESIS OF 1-ALKYNYL KETONES
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2-Lithio-2-(trimethylsilylethynyl)-1,3-dioxane 3 is prepared from 2-(trimethylsilylethynyl)-1,3-dioxane with n-BuLi.Alkylation of 3 produces propargylic ketals 2 exclusively.Reaction with group IV-B chlorotrimethylmetalanes gives both propargylic products 2 and allenes 6 depending on the solvent used.Desilylation of 2 as well as hydrolysis to the alkynyl ketones 1 can be carried out under mild conditions.The first 1-alkynyl stannyl ketone has been prepared in this way.Formation of 2-lithio-2-(3,3-dimethyl-1-butynyl)-1,3-dioxane 10 requires t-BuLi.With various electrophiles 10 yields propargylic products and/or allenes in ratios depending on the solvent used.
- Kruithof, Klaas J. H.,Schmitz, Robert F.,Klumpp, Gerhard W.
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p. 3073 - 3082
(2007/10/02)
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- Some uses of silicon compounds in organic synthesis
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1.The amount of γ-phenylthioalkylation of silyl dienol ethers is increased when the triphenylsilyl ether is used in place of the trimethylsilyl ether.Phenylthiomethylation is the least γ-selective carbon electrophile of several tried so far. 2.The acid-catalysed reactions of a range of γ-silyl tertiary alcohols cleanly give rearrangement, in which the silyl group controls the outcome.The reactions are similar in several respects to the rearrangements of the corresponding pinacols, except that the silicon controlled reactions are usually cleaner and give higher yields.The reaction is particularly useful for setting up quaternary carbon atoms.
- Fleming, Ian
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