Facial Syntheses of Bromobenzothiazines via Catalyst-Free Tandem C–H Amination/Bromination in Water
摘要:
A transition-metal-free and environmentally friendly synthesis method for bromobenzothiazines through tandem C-H amination/bromination was reported. This reaction contains both intramolecular C-H amination and site-selective electrophilic bromination of arenes with NaBr as the bromo source, PhI(OAc)(2) or K2S2O8 as the oxidant, and H2O as the only solvent.
Directed <i>ortho</i> Metalation-Based Methodology. Halo-, Nitroso-, and Boro-Induced <i>ipso-</i>Desilylation. Link to an <i>in situ</i> Suzuki Reaction
作者:Zhongdong Zhao、Victor Snieckus
DOI:10.1021/ol0506563
日期:2005.6.1
[reaction: see text] Treatment of DoM-derived silylated aromatics 2-4 under standard electrophilic halogenation conditions cleanly affords ipso-desilyation products 5-7, while nitration of methoxy-substituted analogues 8, 9 leads to non-ipso isomers 10, 12 and 11, 13, controlled by a silicon steric effect. Sequential ipso-borodesilylation of 2a, 3a, and 20 followed by treatment with aryl halides under