Halogenation of pyrazoloquinolines and pyrazoloisoquinolines. Theoretical analysis of the regioreactivity and cross-coupling of 3-halogen derivatives†
作者:Jan Pawlas、Jeremy Greenwood、Per Vedsø、Tommy Liljefors、Palle Jakobsen、Per Olaf Huusfeldt、Mikael Begtrup
DOI:10.1039/b006435l
日期:——
Selective C* halogenation (I and Br) of pyrazoles 1a, 3a and 4a gave halopyrazoles 5, 7–9, 11, 12. Reactivity differences between 1a, 3a and 4a, and the failure of 2a to give the expected halopyrazoles 6, 10 were explained using calculated relative energies of bromination, and inspection of frontier molecular orbitals. Utility of the prepared halides was demonstrated by a series of palladium-catalysed cross-coupling reactions.
对吡唑 1a、3a 和 4a 进行选择性 C* 卤化(I 和 Br),可得到卤吡唑 5、7-9、11、12。1a、3a 和 4a 之间的反应差异,以及 2a 未能得到预期的卤代吡唑 6、10 的原因,可以通过计算溴化相对能量和检查前沿分子轨道来解释。一系列钯催化的交叉偶联反应证明了所制备卤化物的实用性。