Arylation of diversely substituted hydrazines by tri- and pentavalent organobismuth reagents
作者:Olga Tšubrik、Uno Mäeorg、Rannar Sillard、Ulf Ragnarsson
DOI:10.1016/j.tet.2004.07.020
日期:2004.9
hydrazides to triply protected hydrazines and included a large number of intermediates of principal synthetic interest. In the case of mono- and disubstituted hydrazines the results demonstrate apparent advantages of pentavalent over trivalent reagents, exemplified by fast, highly chemoselective monoarylation of acylhydrazines at the terminal nitrogen. In contrast, trisubstituted hydrazines are more efficiently
在三芳基铋和三芳基铋二乙酸盐试剂的芳基化方面,研究了各种肼衍生物,重点是范围和局限性。在这些试剂中,有一些在其芳环中含有庞大的取代基。所施加的底物涵盖从简单的酰肼到三重保护的肼的范围,并且包括大量具有主要合成意义的中间体。在单取代和二取代的肼的情况下,结果表明五价取代三价试剂的明显优势,例如末端氮原子上快速,高度化学选择性的酰肼单芳基化。相反,三取代肼更有效地被三价试剂取代。对于这些底物,偶尔会观察到空间因素的强烈影响,反映在较低的收率甚至完全抑制反应上。使用逐步或一锅法将两个不同的芳族取代基引入二取代的肼中。