RESUMO
Reactions that were once the exclusive province of synthetic catalysts can increasingly be addressed using biocatalysis. Through discovery of unnatural enzyme reactions, biochemists have significantly expanded the reach of enzymatic catalysis to include carbene transfer chemistries including olefin cyclopropanation. Here we describe hemoprotein cyclopropanation catalysts derived from thermophilic bacterial globins that react with diazoacetone and an unactivated olefin substrate to furnish a cyclopropyl ketone, a previously unreported reaction for enzyme catalysts. We further demonstrate that the resulting cyclopropyl ketone can be converted to a key cyclopropanol intermediate that occurs en route to the anti-hepatitis C drug grazoprevir.
Assuntos
Proteínas de Bactérias/química , Ciclopropanos/síntese química , Hemeproteínas/química , Propanóis/síntese química , Alcenos/química , Amidas , Compostos Azo/química , Proteínas de Bactérias/genética , Biocatálise , Carbamatos , Ciclização , Evolução Molecular Direcionada , Hemeproteínas/genética , Estrutura Molecular , Mutagênese Sítio-Dirigida , Estudo de Prova de Conceito , Quinoxalinas/química , Sulfonamidas , Verrucomicrobia/químicaRESUMO
An efficient route to the HCV antiviral agent uprifosbuvir was developed in 5 steps from readily available uridine in 50% overall yield. This concise synthesis was achieved by development of several synthetic methods: (1) complexation-driven selective acyl migration/oxidation; (2) BSA-mediated cyclization to anhydrouridine; (3) hydrochlorination using FeCl3/TMDSO; (4) dynamic stereoselective phosphoramidation using a chiral nucleophilic catalyst. The new route improves the yield of uprifosbuvir 50-fold over the previous manufacturing process and expands the tool set available for synthesis of antiviral nucleotides.
RESUMO
A novel synthesis of vernakalant is described. Using inexpensive and readily available reagents, the key transformations involve (1) an efficient zinc-amine-promoted etherification, (2) a highly stereoselective enzyme-catalyzed dynamic asymmetric transamination to set up the two contiguous chiral centers in the cyclohexane ring, and (3) a pyrrolidine ring formation via alkyl-B(OH)2-catalyzed amidation and subsequent imide reduction.