A C–H Borylation Approach to Suzuki–Miyaura Coupling of Typically Unstable 2–Heteroaryl and Polyfluorophenyl Boronates
摘要:
A method for the synthesis of biaryls and heterobiaryls from arenes and haloarenes without the intermediacy of unstable boronic acids is described. Pinacol boronate esters that are analogous to unstable boronic acids are formed in high yield by iridium-catalyzed C-H borylation of heteroarenes and fluoroarenes. These boronates are stable in the solid state or in solution and can be generated and used in situ. They couple with aryl halides in the presence of simple palladium catalysts, providing a convenient route to biaryl and heteroaryl products that have been challenging to prepare via boronic acids.
stereoselective base-catalyzed (Cs2CO3/DMSO) intramolecular cyclization of the synthesized propargylic derivatives to form (acylmethylidene)pyrrolo[1,2-a]pyrazines of Z-configuration. A concise transition-metal-free strategy for the synthesis of pyrrolo[1,2-a]pyrazines with enone substituents has been developed. It includes the following key steps: (a) cross-coupling of pyrroles with acyl(bromo)acetylenes in solid
摘要 开发了一种简洁的无过渡金属合成具有烯酮取代基的吡咯并[1,2- a ]吡嗪的策略。它包括以下关键步骤:(a)吡咯与固体氧化铝中的酰基(溴)乙炔在室温下交叉偶联,得到2-(酰基乙炔基)吡咯;(b)将炔丙基胺加到上述乙炔中,形成相应的N-炔丙基亚氨基;(c)合成的炔丙基衍生物的化学和立体选择性碱催化的(Cs 2 CO 3 / DMSO)分子内环化反应形成Z-构型的(酰基亚甲基)吡咯并[1,2- a ]吡嗪。 开发了一种简洁的无过渡金属合成具有烯酮取代基的吡咯并[1,2- a ]吡嗪的策略。它包括以下关键步骤:(a)吡咯与固体氧化铝中的酰基(溴)乙炔在室温下交叉偶联,得到2-(酰基乙炔基)吡咯;(b)将炔丙基胺加到上述乙炔中,形成相应的N-炔丙基亚氨基;(c)合成的炔丙基衍生物的化学和立体选择性碱催化的(Cs 2 CO 3 / DMSO)分子内环化反应形成Z-构型的(酰基亚甲基)吡咯并[1