Mono N-arylation of piperazine(III): metal-catalyzed N-arylation and its application to the novel preparations of the antifungal posaconazole and its advanced intermediate

A novel application of Pd0-catalyzed arylation to mono N-arylated piperazines, its mechanism, and its application towards the novel syntheses of the key differentially N,N′-diarylated piperazine antifungal intermediate N-(4-hydroxyphenyl)-N′-(4-aminophenyl)piperazine 5 as well as posaconazole 1 are described.