Highly efficient borylation Suzuki coupling process for 4-bromo-2-ketothiazoles: straightforward access to micrococcinate and saramycetate esters.

The first palladium-catalyzed borylation of 4-bromo-2-ketothiazoles followed by a Suzuki cross-coupling reaction with haloheteroaromatics using Buchwald's Cy-JohnPhos and XPhos ligands is reported. The methodology has allowed the fast preparation of highly valuable 4-pyridinyl- and 4-thiazolyl-2-ketothiazoles as common subunits of thiopeptide antibiotics. As direct applications, novel concise syntheses of a sulfomycinamate thio-analogue as well as micrococcinate and saramycetate esters are described.