Unprotected Indazoles Are Resilient to Ring-Opening Isomerization: A Case Study on Catalytic C–S Couplings in the Presence of Strong Base
作者:Jacob M. Ganley、Charles S. Yeung
DOI:10.1021/acs.joc.7b02712
日期:2017.12.15
Indazoles represent a privileged scaffold in medicinal chemistry. In the presence of strong base, however, N-protected indazoles are prone to an undesirable ring-opening reaction to liberate o-aminobenzonitriles. By employing unprotected indazoles with a free N–H bond, isomerization is averted because the heterocycle is deprotonated in situ. We herein report functional group-tolerant and robust C–S
吲唑是药物化学中的一种特殊支架。然而,在强碱的存在下,N-保护的吲唑易于发生不希望的开环反应以释放邻氨基苯甲腈。通过使用带有NH键的未保护的吲唑,由于杂环被原位去质子化,因此可以避免异构化。我们在本文中报道了在双(三甲基甲硅烷基)酰胺锂存在下,溴吲唑与具有不同电子性质的硫醇的官能团耐受性和稳健的C–S偶联。