Synlett

Herein, we report a simple and noninvasive experimental protocol in which a series of relative reaction rates may be obtained by way of single competition experiments. This approach permits a quantitative comparison of any given number of chiral catalysts relative to a ‘benchmarking’ chiral catalyst – a particularly useful tool since catalyst design and selection have remained largely dependent on chemical intuition. We apply this benchmarking approach towards an asymmetric N-heterocyclic carbene (NHC) catalyzed intramolecular Stetter reaction as a proof-of-concept study. In doing so, we demonstrate a rapid method to assess the complex interplay between catalyst reactivity and stereoelectronic effects – an analytical approach that has heretofore not been attempted for NHCs. To showcase the generality of this method, we apply it to an enantioselective Rh(I)-catalyzed [2+2+2] cycloaddition of alkenyl isocyanates and aryl alkynes for a series of chiral phosphoramidite ligands. The results described herein demonstrate that this inexpensive and easily adoptable protocol can reveal complex yet subtle steric and stereoelectronic effects of vastly different chiral catalyst structures, which can further aid with catalyst development and selection for a clearly defined application.

Aryl-glycosides represent a significant subclass of crucial glycosidic compounds, increasingly capturing the attention of pharmaceutical developers as bioelectronic motifs embedded within glycosides. Their outstanding resistance to enzymatic hydrolysis bestows a distinctive advantage in the field of drug development, particularly in therapeutic domains such as diabetes treatment, where pharmaceuticals based on the C-aryl-glycoside architecture manifest compelling therapeutic efficacy. As a result, researchers in the realm of synthetic chemistry have diligently explored and devised a plethora of streamlined and efficacious synthetic methodologies. This comprehensive account systematically delineates methodologies employed in recent years for the efficient synthesis of C-aryl-glycosides, offering insights into three primary directions: transition-metal catalysis, radical strategies, and metal-free catalysis processes.1 Introduction2 Glycosylation via Transition-Metal Catalytic Approaches3 Glycosylation via Glycosyl Radical Approaches4 Glycosylation via Metal-Free Catalytic Approaches5 Conclusion and Outlook

We developed a redox-neutral synthesis of isoindoloindolone via intramolecular arylation of 2-(1H-indole-1-carbonyl)benzoic acids. This protocol facilitates the formation of various substituted isoindoloindolones in yields ranging from 17% to 80%. Our mechanistic investigations indicate the pivotal role of NaI: the iodide anion promotes the formation of the desired isoindoloindolone, and the sodium cation suppresses the formation of acylated byproducts, thereby enabling the selective formation of isoindoloindolones in acceptable yields.

An attempted aryl selenium-catalyzed formation of cis-chlorohydrins from alkenes was unsuccessful but led to an electrochemical investigation for the trans-selective chloroformyloxylation of cyclic and acyclic alkenes in moderate to good yields. Interestingly, when 1,1-disubstituted alkenes were used, the corresponding vinyl chloride derivatives were obtained, and the application of 1-phenylcyclohex-1-ene led to the formation of an allyl chloride derivative.

Synlett 2024; 35: XV-XVIDOI: 10.1055/s-0043-1763724Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

Over the past two decades, bioorthogonal chemistry has profoundly impacted various chemistry-related fields, including chemical biology and drug delivery. This transformative progress stems from collaborative efforts involving chemists and biologists, underscoring the importance of interdisciplinary research. In this Account, we present the developments in bioorthogonal chemistry within our Institute for Molecules and Materials at Radboud University. The chemistry disclosed here spans from strained alkynes and alkenes to drug release and bioconjugation strategies, mirroring the extensive scope provided by bioorthogonal chemistry. By reflecting on the chemistry originating at Radboud University, this Account emphasizes that teamwork is essential for driving significant progress in bioorthogonal chemistry.1 Introduction2 Providing BCN as a Robust Bioorthogonal Tool for Chemical Biology and Beyond3 Towards Readily Available Click-to-Release trans-Cyclooctenes4 Giving Molecules Guidance5 Next Generation of Bioconjugation Strategies: Dynamic Click Chemistry6 Conclusions

The nickel-catalyzed borylative coupling of aldehydes and 1,3-dienes with diboron reagents offers an efficient method for synthesizing valuable homoallylic alcohols from easily accessible starting materials. However, achieving enantioselectivity in this reaction has been a significant challenge. We discuss our recent report on the first example of a nickel-catalyzed enantioselective borylative coupling of aldehydes with 1,3-dienes, employing a chiral spiro-phosphine–oxazoline ligand. Notably, by utilizing (E)-1,3-dienes or (Z)-1,3-dienes, we can reverse the diastereoselectivity, yielding either anti- or syn-products, respectively.

Synlett 2024; 35: A53-A69DOI: 10.1055/s-0040-1720628Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

Synlett 2024; 35: V-DOI: 10.1055/s-0043-1763694Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

Synlett 2024; 35: 734-734DOI: 10.1055/s-0043-1763692Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents  |  Full text