Palladium-catalyzed carbonylative coupling of pyridine halides with aryl boronic acids
作者:Samuel Couve-Bonnaire、Jean-François Carpentier、André Mortreux、Yves Castanet
DOI:10.1016/s0040-4020(03)00342-9
日期:2003.4
The main side-products arise from direct, non-carbonylative cross-coupling. Under optimized conditions, benzoylpyridines are recovered in high yields (80–95%). The order of reactivity decreases from iodo- to bromopyridines and from 2-, 4- to 3-substituted halopyridines. The reactivity of dihalopyridines has been investigated; 2,6-dibromopyridine (7) and 3,5-dibromopyridine (11) are selectively transformed
的各种单iodopyridines和溴吡啶(的carbonylative Suzuki交叉偶联1A,b,图3a - Ç,5通过钯-膦体系催化已经被研究以制备苯甲酰基吡啶衍生物()2,4,6)。选择性和反应速率高度依赖于反应条件,即钯催化剂前体的性质,溶剂,温度和CO压力。主要副产物来自直接的非羰基交叉偶联。在最佳条件下,苯甲酰吡啶的收率很高(80-95%)。反应顺序从碘吡啶到溴吡啶,从2-,4-到3-取代的卤吡啶降低。已经研究了二卤吡啶的反应性。2,6-二溴吡啶(7)和3,5-二溴吡啶(11)被选择性地转化为任一相应的苯甲酰基苯基吡啶(8,12)或相应的二苯甲酰基(9,13)。不对称的2,5-二卤代吡啶(15a,b)以高收率转化成2-苯甲酰基-5-溴吡啶(16)或2,5-二苯甲酰基吡啶(17)。