Synlett

As a special class of cyclopropanes, gem-difluorinated cyclopropanes have many fascinating properties as a result of the gem-difluoro substitution; thus, their reactions have received much attention from the synthetic chemistry community. Recently, gem-difluorinated cyclopropanes have gradually emerged as a type of novel and unique fluorinated allylic synthon in cross-coupling reactions for the synthesis of monofluoroalkenes. Herein, we briefly summarize recent advances in transition-metal-catalyzed reactions of gem-difluorinated cyclopropanes.1 Introduction2 Palladium-Catalyzed Reactions with Linear Selectivity3 Palladium-Catalyzed Reactions with Branched Selectivity4 Other Metal-Catalyzed Reactions5 Conclusions

Domino conjugate addition/inert-bond activation is a useful strategy for improving the efficiency of synthesis. We summarize reports on domino conjugate addition/inert-bond activation and its applications in the rhodium-catalyzed ring-expansion and ring-opening reactions of azetidines.1 Introduction2 Rhodium-Catalyzed Domino Conjugate Addition/β-C Cleavage/ Protonation3 Rhodium-Catalyzed Domino Conjugate Addition/N-Directed α-C(sp3)–H Activation4 Conclusion

We reported a nickel-catalyzed enantioconvergent deaminative alkylation of α-amino acid derivatives with unactivated olefins, providing an efficient and convenient access to a range of α-enantioenriched amides. This method represents the first example of enantioselective deaminative functionalization with racemic amine precursors and features in mild conditions and broad substrate scope. New sterically encumbered bis(oxazoline) ligand was developed to improve both reactivity and enantioselectivity, which is key to the success of this reaction.

Herein we report a method for pyrrole synthesis via iron-catalyzed carboamination/copper-mediated cyclization that is completely regioselective for the formation of 1,2,4-trisubstituted products. This two-step, one-pot process offers significant improvements to previously reported conditions including the use of a readily available copper(I) source and a markedly less arduous experimental procedure. Exploration of the substrate scope reveals a variety of arylacetylenes undergo pyrrole formation to afford single isomer products. Isotopic labelling data points to a mechanism involving activation of the alkyne moiety by the copper(I) reagent during the cyclization step.

Synlett 2022; 33: V-DOI: 10.1055/s-0042-1752338Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

Synlett 2022; 33: A151-A166DOI: 10.1055/s-0040-1720575Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

In this paper, a novel and efficient method is reported for the synthesis of novel 2-substituted 3-thioxoisoindolin-1-one derivatives. The method is based on the solvent-free reaction of 2-carboxybenzaldehyde with aliphatic amines and sulfur at 100 °C. This reaction is intensely significant, especially in pharmacy applications, due to the facile synthesis of asymmetric thioxoisoindolin-1-one derivatives with phthalimide backbones.

α-Metalated isocyanides are a versatile class of compounds that can easily be employed in various transformations, affording tangible libraries for screening campaigns. We report the ring-opening reactions of cyclic anhydrides and lactones with three different metalated isocyanides that readily give 4,5-disubstituted oxazoles, including useful drug-like synthetic intermediates with two functional groups as handles for further modifications.

A nine-step synthetic sequence to linear tetraquinanes involving [3+2] cycloaddition, chemoselective allylation, and ring-rearrangement metathesis as key steps is reported. A chemoselective allylation of 7-ketonorbornene was realized for the first time by using indium powder and allyl bromide. By this method, norbornene ketones can be selectively allylated in the presence of a cyclopentanone moiety to give good yields of monoallylated Barbier-type products.

A transition-metal-free novel route to access N-(o-halo)arylsulfoximines/sulfonimidamides is achieved by the reaction of sulfoximine/sulfonimidamide, aryne precursor, and CCl4/CBr4 in the presence of KF/18-crown-6. The in situ generated benzyne intermediate (from silyl aryl triflate) reacts with the nucleophile (sulfoximine/sulfonimidamide) and halide source (CCl4/CBr4) to yield the product in moderate to good yield. The protocol exhibits broad substrate scope. The regioisomers formed from the unsymmetric aryne precursor were separated effectively via column chromatography.