Synthesis and Structure-Activity Relationship of Covalent Inhibitors of SARS-CoV-2 Papain-Like Protease with Antiviral Potency.

The papain-like protease (PLpro) is a highly conserved domain encoded by the coronavirus (CoV) genome and it plays an essential role in the replication and maturation of the virus in addition to weakening host immune response. Due to the virus's reliance on PLpro for survival and propagation, small-molecule inhibitors of PLpro serve as an attractive model for direct-acting antiviral therapeutic agents against SARS-CoV-2. Building upon existing work aimed at designing covalent inhibitors against PLpro, we report the synthesis and structure-activity relationship of analogs based on the known covalent inhibitor 1 (Sanders, et al.

Scalable Thiol Reactivity Profiling Identifies Azetidinyl Oxadiazoles as Cysteine-Targeting Electrophiles.

Cysteine reactive groups are a mainstay in the design of covalent drugs and probe molecules, yet only a handful of electrophiles are routinely used to target this amino acid. Here, we report the development of scalable thiol reactivity (STRP), a method which enables the facile interrogation of large chemical libraries for intrinsic reactivity with cysteine. High throughput screening using STRP identified the azetidinyl oxadiazole as a moiety that selectively reacts with cysteine through a ring opening-based mechanism, capable of covalently engaging cysteine residues broadly across the human proteome.

Total Synthesis of Benzofuran-Based Aspergillusene B via Halogenative Aromatization of Enones.

A novel "non-aromatic pool" synthetic strategy for the synthesis of benzofuran-based natural products via oxidative haloaromatization of enones is reported. This approach is successfully applied in the first total synthesis of the natural product aspergillusene B. In comparison with a separately executed "aromatic pool" synthesis, the "non-aromatic pool" protocol demonstrates equivalent efficiency but offers a much higher degree of modularity.

Short Enantioselective Formal Synthesis of (-)-Platencin.

A short enantioselective formal synthesis of the antibiotic natural product platencin is reported. Key steps in the synthesis include enantioselective decarboxylation alkylation, aldehyde/olefin radical cyclization, and regioselective aldol cyclization.

Total Synthesis of Grifolin, Grifolic Acid, LL-Z1272α, LL-Z1272β, and Ilicicolinic Acid A.

A novel synthetic approach for the synthesis of bioactive phenolic natural products is reported. This strategy highlights the power of halogenative aromatization reactions recently developed in our group for preparing densely functionalized arenes in a controlled fashion. Five natural products related by an aromatic core and a farnesyl side chain are synthesized.