Lithium trihydroxy/triisopropoxy-2-pyridylborate salts (LTBS): synthesis, isolation, and use in modified Suzuki-Miyaura cross-coupling reactions

摘要

We describe herein shelf-stable, isolable, and characterizable pyridyl lithium trihydroxy and triisoprop-oxy 2-borate salts (LTBS) for use in modified Suzuki-Miyaura cross-coupling reactions that can be produced in quantities greater than one hundred grams. Pyridyl LTBS provide a viable cross-coupling alternative to unstable 2-pyridylboronic acids, boronates, and trifluoroborate salt derivatives. We also demonstrate the synthesis and cross-coupling of shelf-stable LTBS reagents of other sp~2-hybridized nitrogen-containing heterocycles including thiazole, pyrazine, quinoline, and isoquinoline heterocycles.