O-Allylated Pudovik and Passerini Adducts as Versatile Scaffolds for Product Diversification

International audienc

Synthesis of CHF2-containing heterocycles through oxy-difluoromethylation using low-cost 3D printed PhotoFlow reactors

We report here a highly straightforward access to a variety of CHF2-containing heterocycles, including lactones, tetrahydrofurans, tetrahydropyrans, benzolactones, phthalanes, and pyrrolidines, through a visible light-mediated intramolecular oxy-difluoromethylation under continuous flow. The method, which relies on the use of readily available starting materials, low-cost 3D printed photoflow reactors, and difluoromethyltriphe-nylphosphonium bromide used here as a CHF2 radical precursor, is practical and scalable and provides the desired products in moderate to excellent yields and excellent regio- and stereoselectivitie

In situ targeted activation of an anticancer agent using ultrasound-triggered release of composite droplets

International audienc

Utilisation de dérivés de diamines bis-sulfonylées de symétrie C2 comme agents d'acétylation énantiosélective pour la résolution cinétique d'amines (Mise au point de nouvelles résines fonctionnalisées pour la synthèse sur phase solide)

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Straightforward Synthesis of the Near-Infrared Fluorescent Voltage-Sensitive Dye RH1691 and Analogues Thereof

International audienceA highly straightforward synthesis of the near-infrared voltage-sensitive dye RH1691 is reported featuring two sequential anionic additions of C-nucleophilic heterocycles on a cyanine. This convergent approach led to the synthesis of four new probes, which also exhibit fluorescence in the near-infrared region

Synthesis of α-Difluoromethyl aryl ketones through a photoredox difluoromethylation of enol silanes

We report here an efficient and highly straightforward access to α-difluoromethylated ketones through a visible light-mediated difluoromethylation of readily available enol silanes. The method, which takes advantage of the polyvalence of Hu’s reagent, N-tosyl-S-difluoromethyl-S-phenylsulfoximine, used here as a CHF2 radical precursor under catalytic photoredox conditions, is practical, scalable, and provides the corresponding α-CHF2 ketones in good to excellent yields

Sequential C-Selective Difluoromethylation/Pd-Catalyzed Decarboxylative Protonation: An Efficient Access to Tertiary Difluoromethylated Scaffolds

We report here a general method that allows a highly straightforward access to tertiary difluoromethylated compounds. The strategy relies on a two-step sequence featuring a C-selective electrophilic difluoromethylation and an unprecedented palladium-catalyzed decarboxylative protonation. Considering the generality of the method and the attractive properties offered by the difluoromethyl group, this approach provides a valuable tool for late-stage functionalization and drug development.<br /

Unlocking copper catalysis with nitro compounds: Synthesis of functionalized allylboranes from allylic nitroalkanes

A copper-catalyzed borylation of allylic nitroalkanes is reported. The method, which exploits the high versatility of the nitroalkane precursors, tolerates a variety of functional groups and allows a straightforward access to diversely substituted allylboronic esters in high yields. This unprecedented reactivity towards copper complexes has been further exploited in the synthesis of a number of γ fluoroallyl boronic esters starting from readily available α fluoroallyl nitroalkanes, as well as in various post-functionalizations towards synthetically useful building blocks. Both the reaction mechanism and the chemoselectivity have been rationalized experimentally and through DFT calculations

Lyngbouilloside and related macrolides from marine cyanobacteria.

International audienceLyngbouilloside and the related macrolides lyngbyaloside, lyngbyaloside B and lyngbyaloside C have attracted a lot of attention over the past decade due to their intriguing architecture, their natural scarcity and their potential biological activities. This review aims to showcase the various strategies that have been used to access these natural products

Active, selective, and stable single-component precatalysts for asymmetric allylic alkylation

The stereoselective construction of new carbon-element bonds is a crucial aspect of organic synthesis. Among the many strategies developed to date, palladium-catalysed asymmetric allylic alkylation is commonly used to access chiral molecules in natural product and active pharmaceutical ingredient synthesis. The use of modular Trost-type ligands and phosphinooxazoline (PHOX) ligands results in generally high stereoselectivity for a wide range of transformations. However, these reactions nearly always require relatively high catalyst loadings (5-10 mol%), reaction-specific catalyst preactivation protocols, and excess chiral ligand to ensure high yield and selectivity. Here we report the isolation and catalytic evaluation of a series of chiral palladium(0) single-component precatalysts that are active for a variety of asymmetric allylic alkylation reactions. The four Trost-type precatalysts in this work are the first characterized examples of stable, isolable Pd complexes with the diphosphines coordinated in the desired κ2-P,P fashion. All of the palladium(0) complexes are stable for >12 months when stored under nitrogen, and can be handled as solids and even in solution under air for hours without decomposition. A catalytic evaluation of these single-component precatalysts across 9 distinct asymmetric allylic alkylation reactions reveals excellent performance in terms of reactivity, selectivity, practicality, and minimizing palladium and chiral ligand loading. This enables both small-scale multivariate screening studies and preparative scale synthesis of key chiral building blocks, exemplified with the unprecedented enantioselective allylation of hydantoins. The optimized reaction achieves high yield and enantioselectivity with only 0.2 mol% of catalyst (turnover number of 465). These precatalysts will enable development of more efficient and robust asymmetric allylic alkylation reactions toward complex target molecules