Jean-Pierre Vors

Recent advances in transition metal-catalyzed Csp2-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

Summary In the last few years, transition metal-mediated reactions have joined the toolbox of chemists working in the field of fluorination for Life-Science oriented research. The successful execution of transition metal-catalyzed carbon–fluorine bond formation has become a landmark achievement in fluorine chemistry. This rapidly growing research field has been the subject of some excellent reviews. Our approach focuses exclusively on transition metal-catalyzed reactions that allow the introduction of –CFH2, –CF2H, –CnF2 n +1 and –SCF3 groups onto sp² carbon atoms. Transformations are discussed according to the reaction-type and the metal employed. The review will not extend to conventional non-transition metal methods to these fluorinated groups.

Trifluoromethyl ethers – synthesis and properties of an unusual substituent

Summary After nitrogen, fluorine is probably the next most favorite hetero-atom for incorporation into small molecules in life science-oriented research. This review focuses on a particular fluorinated substituent, the trifluoromethoxy group, which is finding increased utility as a substituent in bioactives, but it is still perhaps the least well understood fluorine substituent in currency. The present review will give an overview of the synthesis, properties and reactivity of this important substituent.

Microwave-assisted solvent- and ligand-free copper-catalysed cross-coupling between halopyridines and nitrogen nucleophiles

N-Heteroarylated products are obtained in good yields by microwave-assisted solvent- and ligand-free copper-catalysed amination of halopyridines with nitrogen nucleophiles.

A Simple Copper-Catalyzed Synthesis of Tertiary Acyclic Amides

The N-arylation of aromatic and aliphatic secondary acyclic amides, known to be poor nucleophiles, has been accomplished using a simple and cheap copper catalytic system. The corresponding tertiary acyclic amides, which can be found in numerous biologically active compounds, have been obtained in good to excellent yields.

A modular sydnone cycloaddition/Suzuki-Miyaura cross-coupling strategy to unsymmetrical 3,5-bis(hetero)aromatic pyrazoles.

The [3 + 2] dipolar cycloaddition of 4-halosydnones with 1-haloalkynes opens a straightforward access to 3,5-dihalopyrazoles, valuable scaffolds for the elaboration of unsymmetrically 3,5-substituted pyrazole derivatives via site-selective Pd-catalyzed cross-coupling reactions. For instance, the flexible introduction of different (hetero)aryl substituents at the C-5 and C-3 positions of the PMP-protected pyrazole nucleus was achieved in a one-pot operation via sequential reactions with various boronic acids.

Solid-phase synthesis of natural product-like macrocycles by a sequence of Ugi-4CR and SNAr-based cycloetherification

An on-resin Ugi four-component reaction followed by an intramol. nucleophilic arom. substitution (SNAr) has been developed for the rapid access to biaryl-ether contg. macrocycles. Supported isocyanide was prepd. and used together with heptanal, butylamine, and 3-hydroxyphenylacetic acid for on-resin Ugi four-component reaction. [on SciFinder (R)]

Asymmetric Total Synthesis of the Immunosuppressant (! )-Pironetin**

Independently isolated by Yoshida et al. and Kobayashi and co-workers from Streptomyces sp. NK-10958 and the fermentation broths of Streptomyces prunicolor PA-48153, ( )-Pironetin (1) was found to display plant-growth-regulatory as well as immunosuppressive activities similar to those exhibited by cyclosporin A (CsA) and FK-506. More recently, ( )-pironetin has since been identified as a strong antitumor agent that influences the dynamics of the tubulin– microtubules system by inhibiting the polymerization of tubulin. Interestingly, whereas other antitumor agents such as colchicin, vinblastin, rhizoxin, and epothilone B, bind to btubulin, ( )-pironetin was shown to bind to the a subunit of tubulin.

Phosphorus dendrimers as new tools to deliver active substances

Abstract An active substance having pesticide properties is linked to the surface of phosphorus-containing dendrimers through a linker. Depending on the chemical stability of the linker towards hydrolysis, the release of the active substance can be controlled.

New Synthesis of A‐Ring Aromatic Strigolactone Analogues and Their Evaluation as Plant Hormones in Pea (Pisum sativum)

A new general access to A-ring aromatic strigolactones, a new class of plant hormones, has been developed. The key transformations include in sequence ring-closing metathesis, enzymatic kinetic resolution and a radical cyclization with atom transfer to install the tricyclic ABC-ring system. The activity as plant hormones for the inhibition of shoot branching in pea of various analogues synthesized by this strategy is reported.

In Situ Generated Fluorinated Iminium Salts for Difluoromethylation and Difluoroacetylation

The use of TFEDMA, a fluoroalkyl amino reagent, for the difluoromethylation and difluoroacylation of arenes, heteroarenes, and C-H acidic compounds is reported. This approach allows for an efficient access to difluoromethylated products of high added value in good to excellent yields and with scale-up possibilities.