RESUMEN
We describe the development of the practical manufacturing of Ensitrelvir, which was discovered as a SARS-CoV-2 antiviral candidate. Scalable synthetic methods of indazole, 1,2,4-triazole and 1,3,5-triazinone structures were established, and convergent couplings of these fragments enabled the development of a concise and efficient scale-up process to Ensitrelvir. In this process, introducing a meta-cresolyl moiety successfully enhanced the stability of intermediates. Compared to the initial route at the early research and development stage, the overall yield of the longest linear sequence (6 steps) was improved by approximately 7-fold. Furthermore, 9 out of the 12 isolated intermediates were crystallized directly from each reaction mixture without any extractive workup (direct isolation). This led to an efficient and environmentally friendly manufacturing process that minimizes waste of organic solvents, reagents, and processing time. This practical process for manufacturing Ensitrelvir should contribute to protection against COVID-19.
RESUMEN
The first example of enantioselective intermolecular cycloaddition of carbonyl ylides with indoles is described. The cycloaddition of five- and six-membered carbonyl ylides derived from diazodiketoesters with N-methylindoles under catalysis by dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh(2)(S-TCPTTL)(4), gave cycloadducts in high yields and with high levels of enantioselectivity (up to 99% ee) as well as excellent exo diastereoselectivity.
