Hydrogen Bonding Phase-Transfer Catalysis with Ionic Reactants: Enantioselective Synthesis of γ-Fluoroamines
作者:Giulia Roagna、David M. H. Ascough、Francesco Ibba、Anna Chiara Vicini、Alberto Fontana、Kirsten E. Christensen、Aldo Peschiulli、Daniel Oehlrich、Antonio Misale、Andrés A. Trabanco、Robert S. Paton、Gabriele Pupo、Véronique Gouverneur
DOI:10.1021/jacs.0c05131
日期:2020.8.19
salts are used as phase-transfer catalysts for fluorination with alkali metal fluorides. We now demonstrate that these organic salts, specifically azetidinium triflates, are suitable substrates for enantioselective ring opening with CsF and a chiral bis-urea catalyst. This process, which highlights the ability of hydrogen bonding phase-transfer catalysts to couple two ionic reactants, affords enantioenriched
铵盐用作碱金属氟化物氟化的相转移催化剂。我们现在证明这些有机盐,特别是氮杂环丁烷三氟甲磺酸盐,是用 CsF 和手性双脲催化剂对映选择性开环的合适底物。该过程突出了氢键相转移催化剂偶联两种离子反应物的能力,以高产率提供了对映体富集的 γ-氟胺。机理研究强调了催化剂在相转移中的作用,并且计算出的过渡态结构解释了对非手性氮杂环丁烷非对映异构体混合物观察到的对映收敛。亲电子试剂中的 N 取代基会影响反应性,但氮的构型对于对映选择性并不重要。