Discovery of HC-7366: An Orally Bioavailable and Efficacious GCN2 Kinase Activator

A series of activators of GCN2 (general control nonderepressible 2) kinase have been developed, leading to HC-7366, which has entered the clinic as an antitumor therapy. Optimization resulted in improved permeability compared to that of the original indazole hinge binding scaffold, while maintaining potency at GCN2 and selectivity over PERK (protein kinase RNA-like endoplasmic reticulum kinase). The improved ADME properties of this series led to robust in vivo compound exposure in both rats and mice, allowing HC-7366 to be dosed in xenograft models, demonstrating that activation of the GCN2 pathway by this compound leads to tumor growth inhibition.

Regioselective Synthesis of Fully Substituted Fused Pyrroles through an Oxidant-Free Multicomponent Reaction

The synthesis of fully substituted fused pyrroles through a multicomponent reaction between a thioamide, an aldehyde, and ammonium acetate is described. This process improves on a route commonly employed in the patent literature by avoiding the use of potentially hazardous oxidants, which cause the formation of side products and require a stringent process of derisking to be utilized on scale. The reaction proceeds under mild conditions, displays excellent functional group tolerance, and facilitates diversification through multiple vectors.

Diastereoselective Synthesis of Morpholine Derivatives from Grignard Reagents and N-Sulfinyl Imines

The stereoselective synthesis of substituted morpholine derivatives has been achieved through a two-step process involving diastereoselective addition of a Grignard reagent to a sulfinyl imine, followed by cyclization.

Hydrogen Atom Transfer-Mediated Cyclisations of Nitriles

Hydrogen atom transfer-mediated intramolecular C-C coupling reactions between alkenes and nitriles, using PhSiH₃ and catalytic Fe(acac)₃ , are described. This introduces a new strategic bond disconnection for ring-closing reactions, forming ketones via imine intermediates. Of note is the scope of the reaction, including formation of sterically hindered ketones, spirocycles and fused cyclic systems.

Copper-Catalyzed Synthesis of Activated Sulfonate Esters from Boronic Acids, DABSO, and Pentafluorophenol

The synthesis of pentafluorophenyl (PFP) sulfonate esters based on the Pd-catalyzed sulfination of aryl and heteroaryl boronic acids is reported. The sulfinate intermediates are converted in situ to the corresponding sulfonate esters using a copper-catalyzed oxidative process, providing a broad range of PFP esters in good yields.

Oxidative β-C-H sulfonylation of cyclic amines

A new and efficient process to access β-functionalisation of cyclic amines via a mild oxidative β-sulfonylation.

A transition metal-free strategy for the dehydrogenative β-sulfonylation of tertiary cyclic amines is described. N-Iodosuccinimide facilitates regioselective oxidative sulfonylation at C–H bonds positioned β to the nitrogen atom of tertiary amines, installing enaminyl sulfone functionality in cyclic systems. Mild reaction conditions, broad functional group tolerance and a wide substrate scope are demonstrated. The nucleophilic character of the enaminyl sulfone is harnessed, demonstrating potential application for scaffold diversification.

The development and mechanistic investigation of a palladium-catalyzed 1,3-arylfluorination of chromenes

A mild palladium-catalyzed ligand-controlled regioselective 1,3-arylfluorination of 2[H]-chromenes has been developed.

A mild palladium-catalyzed ligand-controlled regioselective 1,3-arylfluorination of 2[H]-chromenes has been developed. The products with a syn-1,3 substitution pattern were obtained with high enantiomeric excess using a PyrOx ligand, wherein the utility of these pyranyl-fluorides was further demonstrated through their participation in a diastereoselective C–C bond forming reaction. Ligand dependent divergent formation of both the 1,3- and 1,2- alkene difunctionalization products was observed. The nature of this bifurcation was investigated through experimental studies in combination with computational and statistical analysis tools. Ultimately, the site selectivity was found to rely on ligand denticity and metal electrophilicity, the electronics of the boronic acid, and the donor ability of the directing group in the substrate.

Transition-Metal-Free Amine Oxidation: A Chemoselective Strategy for the Late-Stage Formation of Lactams

A metal-free strategy for the formation of lactams via selective oxidation of cyclic secondary and tertiary amines is described. Molecular iodine facilitates both chemoselective and regioselective oxidation of C-H bonds directly adjacent to a cyclic amine. The mild conditions, functional group tolerance, and substrate scope are demonstrated using a suite of diverse small molecule cyclic amines, including clinically approved drug scaffolds.

Asymmetric palladium-catalyzed directed intermolecular fluoroarylation of styrenes

A mild catalytic asymmetric direct fluoro-arylation of styrenes has been developed. The palladium-catalyzed three-component coupling of Selectfluor, a styrene and a boronic acid, provides chiral monofluorinated compounds in good yield and in high enantiomeric excess. A mechanism proceeding through a Pd(IV)-fluoride intermediate is proposed for the transformation and synthesis of an sp(3) C-F bond.

Gold Catalysed Redox Synthesis of Imidazo[1,2-a]pyridine using Pyridine N-Oxide and Alkynes

A mild, catalytic, atom economical synthesis of imidazo[1,2-a]pyridines has been developed: catalytic PicAuCl2 in the presence of an acid produces a range imidazo[1,2-a]pyridines in good yield. This strategy is mild and forseen to be of particular use for the installation of stereogenic centers adjacent to the imidazo[1,2-a]pyridine ring without loss of enantiomeric excess.

Synthesis of the anti-trypanosomal agent (±)-hydroxyanthecotulide by Cr(ii)-catalysed allylation and Meyer-Schuster rearrangement

The first synthesis of the bioactive sesquiterpene lactone hydroxyanthecotulide is achieved in 7 steps, involving a stereocontrolled Cr(ii)-catalysed reaction of 3-(bromomethyl)furan-2(5H)-one with enynal 9 and a mild Au(i)-catalysed Meyer-Schuster rearrangement.

Catalytic asymmetric synthesis of (+)-anthecotulide using enyne and Meyer-Schuster rearrangements

The bioactive sesquiterpene lactone (+)-anthecotulide (1) is synthesized for the first time, in a six-step sequence devoid of protecting groups. The key transformations are a novel Rh(I)-catalyzed asymmetric enyne rearrangement of a terminal alkynyl ester (4), to form the α-methylene-γ-butyrolactone core, and a final-step mild Au(I)-catalyzed Meyer-Schuster rearrangement.

Stereoselective synthesis of β-(hydroxymethylaryl/alkyl)-α-methylene-γ-butyrolactones

Zinc or a chromium(II) source with 3-(bromomethyl)furan-2(5H)-one (3) and an aldehyde gives β-(hydroxymethylaryl/alkyl)-α-methylene-γ-butyrolactones 5 in good yields and high diastereoselectivities. The methodology is demonstrated in concise syntheses of (±)-hydroxymatairesinol (8) and (±)-methylenolactocin (10) by subsequent arylboronate conjugate addition and translactonization, respectively.