A radical solution: A highly regioselective copper(II)‐catalyzed oxyamination of N‐acyl indoles with oxaziridines gave aminal products that could be converted in a single step into 3‐aminoindoles and ...3‐aminopyrroloindolines (see scheme). When a chiral N‐acyl group was used, the core fragment of some architecturally fascinating pyrroloindoline alkaloids was formed with 91 % ee. Bs=benzenesulfonyl, Moc=methoxycarbonyl.
Molnupiravir (MK-4482) is an investigational antiviral agent that is under development for the treatment of COVID-19. Given the potential high demand and urgency for this compound, it was critical to ...develop a short and sustainable synthesis from simple raw materials that would minimize the time needed to manufacture and supply molnupiravir. The route reported here is enabled through the invention of a novel biocatalytic cascade featuring an engineered ribosyl-1-kinase and uridine phosphorylase. These engineered enzymes were deployed with a pyruvate-oxidase-enabled phosphate recycling strategy. Compared to the initial route, this synthesis of molnupiravir is 70% shorter and approximately 7-fold higher yielding. Looking forward, the biocatalytic approach to molnupiravir outlined here is anticipated to have broad applications for streamlining the synthesis of nucleosides in general.
We have discovered that the oxaziridine-mediated copper-catalyzed aminohydroxylation reaction recently discovered in our laboratories is dramatically accelerated in the presence of halide additives. ...The use of this more active catalyst system enables the efficient aminohydroxylation of electronically and sterically deactivated styrenes and also enables the use of nonstereogenic 3,3-dialkyl oxaziridines as terminal oxidants in the aminohydroxylation reaction. We present evidence that anionic halocuprate(II) complexes are the catalytically active species responsible for the increased reactivity under these conditions. This unexpected observation has led us to re-evaluate our mechanistic understanding of this reaction. On the basis of the results of a variety of radical trapping experiments, we propose a modified mechanism that involves a homolytic reaction of the olefin with a copper(II)-activated oxaziridine. Together, the observation that anionic additives significantly increase the oxidizing ability of oxaziridines and the recognition of the radical nature of reactions of oxaziridines under these conditions suggest that a variety of new oxidative transformations catalyzed by halocuprate(II) complexes should be possible.
Described herein is the synthesis of BMS‐986001 by employing two novel organocatalytic transformations: 1) a highly selective pyranose to furanose ring tautomerization to access an advanced ...intermediate, and 2) an unprecedented small‐molecule‐mediated dynamic kinetic resolution to access a variety of enantiopure pyranones, one of which served as a versatile building block for the multigram, stereoselective, and chromatography‐free synthesis of BMS‐986001. The synthesis required five chemical transformations and resulted in a 44 % overall yield.
Good dynamic: Described is the synthesis of BMS‐986001 by employing two novel organocatalytic transformations: a highly selective pyranose to furanose ring tautomerization, and an unprecedented small‐molecule‐mediated dynamic kinetic asymmetric transformation (DYKAT) to access enantiopure pyranones. BMS‐986001 was synthesized in five steps in an overall yield of 44 %. Bz=benzoyl.
Herein, we present a strategy for the preparation of 3′-fluorinated nucleoside analogues via the aminocatalytic, electrophilic fluorination of readily accessible and bench-stable 2′-ketonucleosides. ...Initially developed to facilitate the manufacture of 3′-fluoroguanosine (3′-FG)a substructure of anticancer therapeutic MK-1454this strategy has been extended to the synthesis of a variety of 3′-fluoronucleosides. Finally, we demonstrate the utility of the 2′-ketonucleoside synthon as a platform for further diversification and suggest that this methodology should be broadly applicable to the discovery of novel nucleoside analogues.
A kilogram-scale synthesis of a key fragment of Ulevostinag (MK-1454), a cyclic dinucleotide agonist of the stimulator of interferon genes (STING), is described. Ulevostinag comprises two non-natural ...nucleoside derivatives linked together via two P-chiral phosphorothioate groups. The strategy utilized to prepare one of these nucleosides, namely, 3′-deoxy-3′-α-fluoro-guanosine (3′-FG), hinges on a diastereoselective α-fluorination of a key keto-nucleoside derivative, followed by substrate-directed reduction of the ketone. Herein, we describe the development of a robust and scalable synthesis of this intermediate, a 3′-deoxy-2′-keto-guanosine derivative, from guanosine. Salient features of the approach include activation of the 2′ and 3′-alcohol groups of guanosine as a bis-tosylate, which enables regioselective E2 elimination to simultaneously deoxygenate the 3′-position and generate the 2′-ketone.
Ulevostinag (MK-1454) is a potent cyclic dinucleotide stimulator of interferon genes (STING) that was selected as a clinical candidate for evaluation in multiple solid tumor types. Nucleoside ...analogue 3′-deoxy-3′-α-fluroguanosine (3′FG) is one of two key monomeric subunits comprising Ulevostinag, and its efficient preparation was set as a key deliverable in the development of this novel therapeutic. We recently reported a novel synthetic approach to 3′FG, involving the aminocatalytic electrophilic fluorination and subsequent substrate-directed reduction of an isolable 2′-keto-nucleoside ( i -Bu-3). Herein, we describe the process development of these key stereodefining steps, enabling the kilogram-scale preparation of i-Bu-3′FG (1). Key features of this process include (1) identification of commercially available l-leucine amide as an excellent fluorination catalyst, (2) development of a highly stereoselective (>95:5) intramolecular hydride delivery from the hindered nucleoside β-face, and (3) use of dispersive Raman spectroscopy to guide form control during the crystallization of 1.
Deucravacitinib (BMS-986165) is a deuterated small-molecule TYK2 inhibitor developed for the treatment of numerous autoimmune disorders. While the first-generation discovery chemistry route to access ...deucravacitinib was concise and sufficient to access kilogram quantities of API, impurity control and cost-of-goods concerns necessitated the design of a new route. Once a new route was identified and demonstrated, each step was optimized for yield, purity, robustness, and sustainability. Key accomplishments include (1) the development of a novel cyclocondensation under mild conditions to afford a methylated 1,2,4-triazole with excellent regiocontrol, (2) the development of safe, homogeneous conditions to quench POCl3 following chlorination of a substrate that is sensitive to nucleophilic and basic conditions, (3) the discovery of a robust, scalable “dual-base” palladium-catalyzed C–N coupling reaction, and (4) mechanistic understanding to inform control strategies for a number of process-related impurities in an API step amidation mediated by EDC. Ultimately, the optimized commercial route was successfully scaled up to afford more than a metric ton of deucravacitinib for clinical and commercial use.
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