Scalable Synthesis of (<i>R</i>,<i>R</i>)-<i>N</i>,<i>N</i>-Dibenzyl-2-fluorocyclohexan-1-amine with CsF under Hydrogen Bonding Phase-Transfer Catalysis
Hydrogen bonding phase-transfercatalysis offers a convenient solution to activate safe and economical metal alkali fluorides for enantioselective nucleophilic fluorination. Herein, we demonstrate the scalability of this protocol with the fluorination of 200 g of racemic trans-N,N-dibenzyl-2-bromocyclohexan-1-amine in a mechanically stirred 1 L glass reactor using 0.5 mol % of a bis-urea organocatalyst
氢键相转移催化为激活安全且经济的金属碱金属氟化物提供了一种方便的解决方案,用于对映选择性亲核氟化。在此,我们通过使用 0.5 mol% 的双脲有机催化剂在机械搅拌的 1 L 玻璃反应器中氟化 200 g 外消旋反式- N , N -dibenzyl-2-bromocyclohexan-1-amine 来证明该协议的可扩展性. 在这些实验中,高混合强度(叶轮平均剪切速率 >10 000 s –1; 每单位质量的最大能量耗散 >300 W/kg)。该反应的热安全性通过差示扫描量热法和反应量热法进行评估,将反应指定为 Stoessel 的临界等级 3。
Efficient synthesis of β-amino bromides
作者:Advait S Nagle、Ralph N Salvatore、Byong-Don Chong、Kyung Woon Jung
DOI:10.1016/s0040-4039(00)00330-0
日期:2000.4
beta-Aminoalcohols were smoothly converted to beta-amino bromides using thionyl bromide and DME which were easily isolated without any further purification. Participation by the beta-amino group in brominations not only enhanced reaction rates but also promoted stereo- and regioselectivities. (C) 2000 Elsevier Science Ltd. All rights reserved.
Hydrogen Bonding Phase-Transfer Catalysis with Potassium Fluoride: Enantioselective Synthesis of β-Fluoroamines
作者:Gabriele Pupo、Anna Chiara Vicini、David M. H. Ascough、Francesco Ibba、Kirsten E. Christensen、Amber L. Thompson、John M. Brown、Robert S. Paton、Véronique Gouverneur
DOI:10.1021/jacs.8b12568
日期:2019.2.20
Potassium fluoride (KF) is an ideal reagent for fluorination because it is safe, easy to handle and low-cost. However, poor solubility in organic solvents coupled with limited strategies to control its reactivity has discouraged its use for asymmetric C-F bond formation. Here, we demonstrate that hydrogenbonding phase-transfer catalysis with KF provides access to valuable β-fluoroamines in high yields
Synthesis, characterization, and nucleophilic ring opening reactions of cyclohexyl-substituted β-haloamines and aziridinium ions
作者:Hyun-Soon Chong、Xiang Sun、Yunwei Chen、Meng Wang
DOI:10.1016/j.tetlet.2014.12.101
日期:2015.2
Cyclohexyl-substituted β-haloamines and aziridinium ions were prepared and characterized. Stereospecific ringopening of aziridinium ions was applied for efficient synthesis of vicinal amine, β-amino acid, and tetrahydroisoquinoline (THIQ) analogues. Nucleophilic ringopening reactions of aziridinium ions and N-protected aziridine analogues were for the first time comparatively studied. The result