- Palladium-Catalyzed Distal m-C-H Functionalization of Arylacetic Acid Derivatives
-
Herein, we present m-C-H olefination on derivatives of phenylacetic acids by tethering with a simple nitrile-based template through palladium catalysis. Notably, the versatility of the method is evaluated with a wide range of phenylacetic acid derivatives for obtaining the meta-olefination products in fair to excellent yields with outstanding selectivities under mild conditions. Significantly, the present strategy is successfully exemplified for the synthesis of drugs/natural product analogues (naproxen, ibuprofen, paracetamol, and cholesterol).
- Srinivas, Dasari,Satyanarayana, Gedu
-
supporting information
p. 7353 - 7358
(2021/10/01)
-
- Surprising and Highly Efficient Use of Methylmagnesium Chloride as a Non-Nucleophilic Base in the Deprotonation and Alkylation of sp3 Centres Adjacent to Nitriles
-
Methylmagnesium chloride (MeMgCl) is a key reagent in research and industry typically as a nucleophile. In this article we develop the use of MeMgCl as a non-nucleophilic base in conjunction with catalytic amounts of an amine mediator. Specifically, we use the base to deprotonate α to a variety of nitriles in alkylation reactions, applying it to the synthesis of a wide variety of tertiary and quaternary nitriles, including examples where we successively and successfully added three different substituents on the carbon α to the nitrile. This method is generally applicable, high yielding and much greener than existing methods, and it has considerable advantages for industrial application.
- Gbadebo, Omolola,Smith, Dennis,Harnett, Ger,Donegan, Gregory,O'Leary, Patrick
-
p. 7037 - 7045
(2019/01/04)
-
- Dual Gold Catalysis: Synthesis of Fluorene Derivatives from Diynes
-
1,5-Diyne systems bearing one terminal and one benzyl- or allyl-substituted alkyne attached to an aromatic backbone were converted in the presence of a gold catalyst. In a dual gold-catalyzed process, gold vinylidenes are formed that selectively undergo formal CH insertion into the C(sp2)–H bond of the offered unsaturated systems. If H atoms are present in the propargylic position, a subsequent isomerization to the aromatic system takes place leading to 9H-fluorene and 11H-benzo[b]fluorene derivatives as final products. In the case of a quaternary carbon in the propargylic position no further aromatization is observed and 10H-benzo[b]fluorene derivatives are obtained in high yield. (Figure presented.).
- Bucher, Janina,Wurm, Thomas,Taschinski, Svenja,Sachs, Eleni,Ascough, David,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
-
supporting information
p. 225 - 233
(2017/02/05)
-
- Substituted benzocarbocycles by palladium-catalyzed cascade reactions featuring a C(sp3) - H activation step
-
Valuable 4- and 5-membered benzocarbocycles were synthesized via selective palladium-catalyzed cascade reactions which combined C(sp3)-H activation, Heck cyclization, Heck arylation or olefin hydrogenation. In all cases, all mechanistically independent steps were catalyzed by a single multi-functional catalyst.
- Hitce, Julien,Baudoin, Olivier
-
p. 2054 - 2060
(2008/09/17)
-
- Inhibitors of Acyl-CoA:Cholesterol Acyltransferase. 4. A Novel Series of Urea ACAT Inhibitors as Potential Hypocholesterolemic Agents
-
We have synthesized a series of N-phenyl-N'-aralkyl and N-phenyl-N'-(1-phenylcycloalkyl)ureas as inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT).This intracellular enzyme is thought to be responsible for the esterification of dietary cholesterol; hence inhibition of this enzyme could reduce diet-induced hypercholesterolemia.For this series of compounds, the in vitro ACAT inhibitory activity was improved by increasing the bulk of the 2,6-substituents on the phenyl ring.Additionally, we found that spacing of the aromatic rings was critical for ACAT inhibitory activity.A phenyl ring five atoms away from the requiste 2,6-diisopropylphenyl moiety was optimal for in vitro activity.Substitution α to the N'-phenyl moiety enhanced in vitro potency.In the case of phenylcycloalkyl ureas, ACAT inhibitory activity was independent of the size of the cycloalkyl ring.From this series of analogs, compound 25, which had excellent in vitro potency for inhibiting ACAT, was found to lower plasma cholesterol by 73percent in vivo when administrated in the diet at 50 mg/kg in an animal model of hypercholesterolemia.In this model, compound 25 lowered plasma cholesterol dose dependently and was as efficacious as the Lederle ACAT inhibitor CL 277082.
- Trivedi, Bharat K.,Holmes, Ann,Stoeber, Terri L.,Blankley, C. John,Roark, W. Howard,et al.
-
p. 3300 - 3307
(2007/10/02)
-
- Trialkyl acyl ammonium halides - A new series of phase transfer catalysts
-
Trialkyl acyl ammonium halides have found to be superior phase transfer catalysts. They were easy to prepare and afford the reactions to be carried out at elevated temperature, owing to their stability.
- Bhalerao,Mathur,Nagabhushan Rao
-
p. 1645 - 1649
(2007/10/02)
-
- Tetrakis-sulphoxides: a New Type of Phase-transfer Catalyst for Nocleophilic Displacements and Alkylations
-
Tetrakis(alkylsulphinylmethyl)methanes have been shown to serve as good phase-transfer catalysts which accelerate SN2 type displacements of octyl bromide with various nucleophiles (thiocyanate, cyanide, phenoxide, and thiolate) in solid-liquid two-phase systems.Alkylation of phenylacetonitrile with alkyl halides has also been carried out in liquid-liquid two-phase systems in the presence of the above sulphoxides to afford the corresponding mono-alkylated products in high yields.
- Fujihara, Hisashi,Imaoka, Koji,Furukawa, Naomichi,Oae, Shigeru
-
p. 333 - 336
(2007/10/02)
-
- The efficiency of diphenylalkylsulfonium salts as alkylating agents
-
A series of the title reagents have been used for the alkylation of a number of nucleophiles including iodide, cyanide, thiocyanate and fluoride ions as well as ethyl acetoacetate, phenylacetonitrile and a variety of nitrogen heterocyclic compounds.The results compared favorably with literature methods.
- Badet, Bernard,Julia, Marc,Lefebvre, Christian
-
p. 431 - 434
(2007/10/02)
-
- SELECTIVE alpha -MONOALKYLATION OF PHENYLACETONITRILE USING ALKALI METAL HYDROXIDE IMPREGNATED ON ALUMINA.
-
In the alkylation of phenylacetonitrile with alkyl halides, alkali metal hydroxides impregnated on alumina act as efficient bases for selective alpha -monoalkylation in benzene. It is proposed that the reaction may take place exclusively in the pore. The selectivity for alpha -monoalkylation is explained in terms of steric hindrance.
- Sukata
-
p. 3306 - 3307
(2007/10/02)
-
- POLYSULFOXIDES AS NEW TYPE OF PHASE TRANSFER CATALYSTS IN TWO PHASE ALKYLATION
-
Tetrakis(hexylsulfinylmethyl)methane(I) and related compounds and polysulfides of crown thiaether(IV) were prepared and found to be used as effective catalysts in the binary phase alkylation of phenylacetonitrile(V) and phenylacetone(VI) with alkyl halides to afford selectively the corresponding monoalkylated products in high yields.
- Furukawa, Naomichi,Imaoka, Koji,Fujihara, Hisashi,Oae, Shigeru
-
p. 1421 - 1424
(2007/10/02)
-
- Wanderungstendenzen cyclischer, polycyclischer und methylverzweigter Alkylreste bei der Beckmann-Umlagerung
-
The migration aptitudes of polycyclic bridgehead groups, cycloalkyl groups as well as of β-, γ- and δ-branched alkyl groups in the Chapman variant of the Beckmann rearrangement were determined.From these data it is concluded that at transition state 2 the migrating group is not resembling a planarised carbenium ion R+, but rather a pentacoordinated carbonium ion structure.Because only small geometrical changes occur in the migrating group vertical stabilisation of charge at transition state is believed to have significant influence on the migration aptitudes.
- Langhals, Heinz,Ruechardt, Christoph
-
p. 3831 - 3854
(2007/10/02)
-
