Synthesis of asymmetric 3,5-diaryl-4H-1,2,6-thiadiazin-4-ones via Suzuki–Miyaura and Stille coupling reactions

摘要: Abstract Asymmetric 3,5-diaryl substituted 4H-1,2,6-thiadiazin-4-ones can be prepared from 3,5-dichloro-4H-1,2,6-thiadiazin-4-one (1) via a multi-step protocol: selective nucleophilic mono-chloro substitution gives either the mono-methoxy or benzyloxy mono-chlorothiadiazinones that phenylated Suzuki–Miyaura coupling. Subsequent BBr3 mediated dealkylation 3-hydroxy-5-phenyl-4H-1,2,6-thiadiazin-4-one (9) activated by modified Finkelstein halodehydroxylation triflate, enabling further arylation reactions using Stille coupling chemistry.