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Abstract. Recyclable supported Au nanoparticles on TiO2 catalyze the cyclization of N‐propargyl or N‐homopropargyl β‐enaminones followed by dehydrogenation (aromatization) leading to substituted 3‐keto pyridines or 4‐picolines in very good yields. This pathway is in contrast to their known cyclization in the presence of Au(I) or Au(III) catalysts which provides 1,4‐oxazepines, instead. The enaminones are formed in situ upon mixing a conjugated allenone or allenyl ester with the alkynylamine, thus the pyridine‐forming transformation is typically a one pot process.
Direct electrochemical oxidative functionalization of caffeine under metal‐free and external‐oxidant‐free conditions have been achieved. Nucleophiles such as various substituted pyrazoles, alcohols and sodium trifluoromethanesulfonate can be utilized with high diastereoselectivity for the dearomatizative functionalization of caffeine. In addition, selective C2 functionalization of caffeine has also been realized with the modification of solvent and reaction time. Gram scale experiment demonstrate the potential application in the derivatization of caffeine.
Abstract. A polystyrene‐immobilized isothiourea has been applied to the enantioselective acylative kinetic resolution (KR) of monoacylated BINOL(s) with inexpensive isobutyric anhydride in batch and flow. High selectivity values (s = 29 at 0 oC) and a remarkable stability of the catalytic system in the operation conditions have been recorded for unsubstituted BINOL. No significant loss of activity/selectivity is recorded after 10 consecutive KR cycles in batch. A continuous flow process has been implemented and operated with a 100 mmol (32.8 g) sample of racemic monoacetylated BINOL in dichloromethane solution in an 84 hours experiment with a packed bed reactor containing 1g (f = 0.37 mmol.g‐1) of the functional resin (s = 17‐21). Residence.
Abstract. A convenient strategy of N‐heterocyclic carbene catalyzed [3+2] cycloaddition of enals with β,γ‐unsaturated α‐ketimino esters is developed. This effective protocol features mild reaction conditions and broad substrate scope, which enables the rapid assembly of various benzoxazinone derived cyclopentanone scaffolds in good to high yields with excellent diastereoselectivities.
An efficient formation of synthetically and biologically relevant β‐ketosulfones via a photo‐mediated decarboxylative ketonization of atropic acids was disclosed. The approach features metal‐free conditions, good functional group compatibility, readily available starting materials and the use of ubiquitous dioxygen as both oxygen source and oxidant. Furthermore, mechanistic studies reveal that the decarboxylative ketonization reaction proceeds via a radical mechanism and may involve a radical chain reaction.
Abstract. The challenging bioamination of hydrophobic substrates has been attained through the employment of a disperse system consisting of a combination of a low polarity solvent (e.g. isooctane or methyl‐tert‐butylether), a non‐ionic surfactant and a minimal amount of water. In these conditions, amine transaminases (ATA) were shown to efficiently carry out the reductive amination of variously substituted cyclohexanones, providing good conversions often coupled with a superior stereoselectivity if compared with the corresponding chemical reductive amination. An array of synthetically useful 4‐substituted aminocyclohexanes was consequentially synthesized for the first time through biocatalysis, analyzed and stereochemically characterized.
An approach for iodofluoroalkylation of unactivated alkynes and alkenes facilitated by an earth‐abundant and inexpensive manganese catalyst, Mn2(CO)10, is reported. This protocol employs visible light as the energy input and shows a wide substrate scope and high functional‐group compatibility. A variety of synthetically useful fluoroalkylated alkyl and alkenyl iodides can be prepared in moderate to excellent yields. The reaction features high efficiency, operational simplicity, scalability, as well as excellent chemo‐, regio‐, and E/Z selectivities.
We report herein a facile approach to tetrahydropyridazines, a scaffold found in many natural products and biologically active entities, via Pd‐catalyzed carboamination of readily available alkenyl hydrazones with aryl and alkenyl halides. Preliminary studies showed its promise for enantioselective synthesis. This work offers an expedient access to tetrahydropyridazine scaffold bearing a variety of substitution patterns, thus significantly increased the availability of these derivatives for downstream evaluation.
Abstract. Reported herein is the construction of chiral aza‐[n.2.1] skeletons by separable epimers of intramolecular [3+2] cross cycloaddition of cyclopropane 1,1‐diesters with chiral sulfinylimines. The epimer products can be separated by silica gel column chromatography.
The palladium‐catalyzed enantioselective C‐H alkenylation of ferrocenecarboxylic acid has been developed. A series of 2‐alkenyl ferrocenecarboxylic acids with planar chirality were obtained using molecular oxygen as an oxidant. This protocol starts from less expensive and readily available starting materials and provides the target products as a key intermediate in organic synthesis.
Access to unprotected 2‐cyano‐glycals via a mild palladium‐catalyzed cyanation of protecting groups‐free 2‐iodoglycals in aqueous media has been developed. Diverse glycal substrates including disaccharide‐type were successfully obtained in good to excellent yields. These unprotected 2‐cyano‐glycal scaffolds were successfully derivatized to different C2‐glycoanalogues.
In this work the patent landscape of catalytic hydrogenation reactions was evaluated with the aid of the online database Patbase®. The respective classifications were used to distinguish the development of trends among patents. The findings give a detailed picture of the patent activity on the field of hydrogenation catalysis and may give the user information on technological areas that occur more often in the patent literature than others.
A straightforward approach for the synthesis of 2‐(3‐arylallylidene)‐3‐oxindoles has been achieved by the dirhodium(II)‐catalyzed reaction of 3‐diazoindolin‐2‐imines with 1‐aryl‐substituted allylic alcohols. This protocol employs easily accessible feedstock to produce oxindole derivatives, which might be applicable in the dye industry. DFT calculations were carried out to gain a mechanistic insight into the reaction.
Synthesis of a wide variety of 3‐amnio‐1H‐inden‐1‐ones from N‐tert‐butyl‐2‐(1‐alkynyl)benzaldimines via intramolecular aminocarbonylation of alkynes using Cs2CO3 as catalyst and air as oxidant has been developed. This highly atom‐efficient, transition‐metal‐free reaction proceeds under thermal conditions. We propose that the reaction proceeds through an unprecedented 5‐exo‐dig cyclization of N‐tert‐butyl‐2‐(1‐alkynyl)benzaldimines and thermal rearrangement of 3‐methylene‐2λ2‐isoindolin‐1‐ols.
An efficient chlorination of indoles and electron‐rich arenes with chlorine anion as nucleophile is described. With the use of ethyl phenyl sulfoxide as the promoter, the reaction went smoothly under metal‐free and mild conditions. Various indoles and electron‐rich arenes are converted into the corresponding chlorinated compounds in moderate to excellent yields. A plausible interrupted Pummerer reaction mechanism was proposed without the oxidation of chloride anion. In addition, the byproduct thioether could be easily converted to the starting material sulfoxide just by a simple oxidation reaction.
Two methods for the synthesis of norbornane‐fused indanes via palladium‐catalyzed three‐component reactions of iodoarenes, norbornenes, and CH2Br2 or α‐diazoesters have been developed. In the reactions, three C–C bonds were constructed and a wide range of norbornane‐fused indanes could be synthesized. The reactions with α‐diazoesters proceeded with a high degree of diastereoselectivity and indanes bearing an all‐carbon quaternary center were formed. The products obtained in the reactions of 1,4‐dihydro‐1,4‐epoxynaphthalene can be converted to fluorenes, providing an alternative way to access fluorene derivatives.
We report a protocol for redox‐neutral Minisci C–H formylation of N‐heteroarenes using 1,3‐dioxoisoindolin‐2‐yl 2,2‐diethoxyacetate as a formyl equivalent at room temperature. This scalable benchtop protocol offers a distinct advantage over traditional reductive carbonylation and Minisci C–H formylation methods in not requiring the use of carbon monoxide, pressurized gas, a stoichiometric reductant, or a stoichiometric oxidant. The high efficiency, broad substrate scope, excellent functional group tolerance, and mildness of this protocol make it particularly suitable for installing an aldehyde on medicinally relevant heterocycles.
1,2‐Boron ate rearrangements represent a fundamental class of transformations to establish new C–C bonds while retaining the valuable boron moiety in the product. In established ionic processes, the boron ate complex is activated by an external electrophile to induce a 1,2‐migration from boron to an adjacent sp3 or sp2 carbon atom. Recently, two complementary radical polar crossover approaches have been explored for both classes, 1,2‐migrations to sp2 and sp3 carbon centers. This review describes the general concepts in this emerging research field and summarizes recent developments of radical induced 1,2‐migrations from boron to carbon.

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