eco-friendly protocol for the chemoselective protection of benzylic and primary and less hindered secondary aliphatic alcohols and phenols as trimethylsilyl ethers and different types of amines as N-tert-butylcarbamates is developed using rice husk (RiH) as the catalyst. This reagent is also able to catalyze the acetylation of alcohols, phenols, thiols and amines with acetic anhydride. Easy work-up, relatively
Saccharin sulfonic acid catalyzed N-Boc protection of amines and formation of tert-butyl ethers from alcohols
作者:F. Shirini、M. A. Zolfigol、M. Abedini
DOI:10.1007/bf03246047
日期:2010.9
(SaSA), as a stable reagent is easily prepared by the reaction of saccharin with neat chlorosulfonic acid at room temperature. This compound is able to catalyze conversion of amines to their corresponding N-Boc protected amines with (Boc)2O. Alcohols were also converted to their corresponding tert-butyl ethers. All reactions took place under mild conditions giving the desired products in good to high
Poly(4-vinylpyridine) catalyzed chemoselective O-TMS protection of alcohols and phenols and N-Boc protection of amines
作者:Farhad Shirini、Nader Ghaffari Khaligh
DOI:10.1007/s13738-011-0060-5
日期:2012.8
Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)2O. All reactions were performed under mild conditions in good to high yields.
Preparation, characterization and application of succinimidinium hydrogensulfate ([H-Suc]HSO<sub>4</sub>) as an efficient ionic liquid catalyst for the N-Boc protection of amines
Succinimidinium hydrogensulfate ([H-Suc]HSO4), which is prepared from the reaction of succinimide and sulfuric acid, showed excellent catalytic activity for theN-Boc protection of various amines under solvent free conditions.
Design of a Photoredox Catalyst that Enables the Direct Synthesis of Carbamate-Protected Primary Amines via Photoinduced, Copper-Catalyzed <i>N</i>-Alkylation Reactions of Unactivated Secondary Halides
作者:Jun Myun Ahn、Jonas C. Peters、Gregory C. Fu
DOI:10.1021/jacs.7b10907
日期:2017.12.13
carbamates with unactivated secondary alkyl bromides at room temperature. Our mechanistic observations are consistent with the newcoppercomplex serving its intended role as a photoredox catalyst, working in conjunction with a second coppercomplex that mediates C-N bond formation in an out-of-cage process.
尽管氮亲核试剂和烷基亲电试剂之间的 SN2 反应历史悠久,但许多此类取代反应仍然遥不可及。近年来,开发过渡金属催化剂以解决这一缺陷的努力已经开始出现。在本报告中,我们解决了将氨基甲酸酯亲核试剂与未活化的仲烷基亲电试剂偶联以生成取代氨基甲酸酯的挑战,这一过程在没有催化剂的情况下无法有效实现;氨基甲酸酯产品本身可用作有机合成中的有用中间体以及生物活性化合物。通过设计和合成一种新的铜基光氧化还原催化剂,带有三齿咔唑/双膦配体,可以在蓝光 LED 灯照射下激活,我们可以在室温下实现一系列伯氨基甲酸酯与未活化的仲烷基溴的偶联。我们的机械观察结果与新的铜配合物作为光氧化还原催化剂的预期作用一致,与第二种铜配合物协同工作,后者在笼外过程中介导 CN 键的形成。