A New Protocol for Selective Deprotection of N-tert-Butoxycarbonyl Protective Group (t-Boc) with Sn(OTf)2
摘要:
A simple and efficient method for the selective removal of N-Boc group by employing tin(II) trifluoromethanesulfonate [Sn(OTf)(2)] in CH2Cl2 or solvent-free conditions was developed. The scope of this procedure is explored for the deprotection of a variety of amines, including amino acid derivatives.
One step direct conversion of azides and benzyl carbamates to t-butyl carbamates is achieved using inexpensive and safe hydride source namely polymethylhydrosiloxane (PMHS) under Pd-C catalysis.
Teaching Old Compounds New Tricks: DDQ-Photocatalyzed C−H Amination of Arenes with Carbamates, Urea, and N-Heterocycles
作者:Somnath Das、Palani Natarajan、Burkhard König
DOI:10.1002/chem.201705442
日期:2017.12.22
The C-H amination of benzene derivatives was achieved using DDQ as photocatalyst and BocNH2 as the amine source under aerobic conditions and visible light irradiation. Electron-deficient and electron-rich benzenes react as substrates with moderate to good product yields. The amine scope of the reaction comprises Boc-amine, carbamates, pyrazoles, sulfonimides and urea. Preliminary mechanistic investigations
Highly<i>ortho</i>-Selective Chlorination of Anilines Using a Secondary Ammonium Salt Organocatalyst
作者:Xiaodong Xiong、Ying-Yeung Yeung
DOI:10.1002/anie.201607388
日期:2016.12.23
An organocatalytic, highly facile, efficient, and regioselective ortho‐chlorination of anilines is described. A secondary ammonium chloride salt has been employed as the catalyst and the reaction can be conducted at room temperature without protection from air and moisture. In addition, the reaction is readily scalable and the catalyst can be recycled and reused. This catalytic protocol has been applied
Synthesis of Substituted Monohalobenzenes via Ortho-Selective Cross-Coupling of Dihalobenzenes with Electron-Donating Ortho-Directing Groups
作者:Kei Manabe、Shunpei Ishikawa
DOI:10.1055/s-2008-1067270
日期:2008.10
Dihalobenzenes that possess directing groups such as OH, CH 2 OH, NH 2 , NHAc, or NHBoc were subjected to ortho-selective cross-coupling with Grignard reagents in the presence of palladium-based catalysts to give the corresponding substituted monohalobenzenes. For the dibromo- and dichlorophenols and anilines, hydroxylated terphenylphosphines 1 and 2 were found to be effective ligands for palladium
We present a blueprint for aromatic C-H functionalization via a combination of photocatalysis and cobaltcatalysis and describe the utility of this strategy for benzene amination and hydroxylation. Without any sacrificial oxidant, we could use the dual catalyst system to produce aniline directly from benzene and ammonia, and phenol from benzene and water, both with evolution of hydrogen gas under unusually