Catalysts and Catalysed Reactions 

About: Catalysts and Catalysed Reactions is an academic journal. The journal publishes majorly in the area(s): Catalysis & Aryl. Over the lifetime, 57 publications have been published receiving 2001 citations.

Metal-free, cooperative asymmetric organophotoredox catalysis with visible light

Abstract: The dawn of old stars: Classic xanthene dyes like eosin Y (gr. eoς=goddess of dawn) and green-light irradiation can replace precious metal complexes for the organocatalytic asymmetric -alkylation of aldehydes rendering the process purely organic.

Copper-catalyzed oxidative trifluoromethylthiolation of aryl boronic acids with TMSCF3 and elemental sulfur

Abstract: Fluorinated functional groups are key structural units found in various pharmaceuticals and agrochemicals. Approximately 30 % of all agrochemicals and 20% of all pharmaceuticals on the market contain fluorine. Among these substituents, the trifluoromethylthio group (CF3S ), especially as an aromatic substituent, plays an important role because of its strong electron-withdrawing effect and high lipophilicity. These characteristics are similar to those of trifluoromethyl (CF3 ) and trifluoromethoxy (CF3O ) groups. Additionally, aryl trifluoromethyl thioethers (CF3SAr) are also key intermediates in the preparation of trifluoromethyl sulfoxide and sulfone, which are important trifluoromethylation reagents. Although impressive progress has been made in the trifluoromethylation of arenes in the past several years, only a few methods are available for the synthesis of aryl trifluoromethyl thioethers. Generally, aryl trifluoromethyl thioethers are prepared either by a nucleophilic reaction of trifluoromethylthiolate with aryl halides, or by a nucleophilic or radical reaction of aryl sulfides and disulfides with a trifluoromethylation reagent. However, these methods are variously limited by a combination of high temperatures, expensive reagents, and low reactivity with electron-rich aromatic groups. Thus, the development of general, safe, and efficient methods to access aryl trifluoromethyl thioethers is highly desirable. Very recently, Buchwald reported a palladium-catalyzed trifluoromethylthiolation of aryl bromides with CF3SAg. [10] This breakthrough for the preparation of ArSCF3 is highly efficient and compatible with a variety of functional groups. However, from the point view of cost-effectiveness and synthetic convenience, using readily available and inexpensive catalysts and fluorinated reagents, such as copper and (trifluoromethyl)trimethylsilane (the Ruppert–Prakash reagent, TMSCF3), to access aryl trifluoromethyl thioethers would be an attractive alternative. The present study was inspired by our own and Buchwald s recent investigations into the copper mediated oxidative trifluoromethylation of arylboronic acid with TMSCF3, [11] as well as Karlin s observation of the formation of a stable copper disulfide complex from the reaction of elemental sulfur (S8) with a Cu I complex. We hypothesized that a Cu disulfide complex generated in situ (II ; Scheme 1) would

Ionic liquid as catalyst and reaction medium – a simple, efficient and green procedure for Knoevenagel condensation of aliphatic and aromatic carbonyl compounds using a task-specific basic ionic liquid

Abstract: The basic ionic liquid 1-butyl-3-methylimidazolium hydroxide, [bmIm]OH, efficiently catalyzes Knoevenagel condensation without requirement of any organic solvent. A wide range of aliphatic and aromatic aldehydes and ketones easily undergo condensations with diethyl malonate, malononitrile, ethyl cyanoacetate, malonic acid and ethyl acetoacetate. The reactions proceed at room temperature and are very fast (10-30 min). However, the most significant feature of this methodology is the condensation of aliphatic aldehyde with diethyl malonate, which is not very easy to achieve by conventional reagents, and was not addressed adequately in literature providing a general and convenient procedure.

Replacing conventional carbon nucleophiles with electrophiles: nickel-catalyzed reductive alkylation of aryl bromides and chlorides

Abstract: A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes The protocols are highly functional-group tolerant (−OH, −NHTs, −OAc, −OTs, −OTf, −COMe, −NHBoc, −NHCbz, −CN, −SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki–Miyaura, Stille, and Hiyama–Denmark reactions Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R–X) and no reaction at the nucleophilic carbon (R–[M]) for organoboron (−Bpin), organotin (−SnMe3), and organosilicon (−SiMe2OH) containing organic halides (X–R–[M

Enantioselective alkynylbenzaldehyde cyclizations catalyzed by chiral gold(I) acyclic diaminocarbene complexes containing weak Au–arene interactions

Abstract: A variety of alcohols is applied in the tandem addition/cycloisomerization process where a bulky substituent at the binaphthyl core of the catalyst is crucial.