Epoxidation with dioxiranes derived from 2-fluoro-2-substituted-1-tetralones and -1-indanones
摘要:
Homochiral 2-fluoro-2-substituted-1-tetralones (10a, 10b, 13) and ethyl 2-fluoro-1-indanone-2-carboxylate (16) have been isolated. The dioxirane derivatives of these ketones have been prepared in situ, and have been shown to epoxidise alkenes but not enantioselectively. The dioxirane derivative of methyl 2,5,7-trifluoro-1-indanone-2-carboxylate (18) has been shown to be comparatively efficient in epoxidation.
Flow electrochemistry: a safe tool for fluorine chemistry
作者:Bethan Winterson、Tim Rennigholtz、Thomas Wirth
DOI:10.1039/d1sc02123k
日期:——
The heightened activity of compounds containing fluorine, especially in the field of pharmaceuticals, provides major impetus for the development of new fluorination procedures. A scalable, versatile, and safe electrochemical fluorination protocol is conferred. The strategy proceeds through a transient (difluoroiodo)arene, generated by anodic oxidation of an iodoarene mediator. Even the isolation of
含氟化合物的活性增强,特别是在制药领域,为新氟化工艺的开发提供了主要动力。提供了一种可扩展、通用且安全的电化学氟化方案。该策略通过碘芳烃介体的阳极氧化产生瞬态(二氟碘)芳烃来进行。甚至二氟化碘( III )的分离也很容易,因为电解是在没有其他试剂的情况下进行的。通过将电解步骤与流动中的下游反应耦合,以高产率实现了广泛的高价碘介导的反应,超越了间歇化学的限制。(二氟碘)芳烃有毒且化学不稳定,因此不间断生成和立即流动使用非常有利。高流速使生产率高达 834 mg h -1,同时大大缩短了反应时间。集成到全自动机器和在线淬火是减少氢氟酸使用带来的危害的关键。
Electrophilic fluorination using a hypervalent iodine reagent derived from fluoride
作者:Gemma C. Geary、Eric G. Hope、Kuldip Singh、Alison M. Stuart
DOI:10.1039/c3cc44792h
日期:——
The air and moisture stable fluoroiodane 8, readily prepared on a 6 g scale by nucleophilic fluorination of the hydroxyiodane 7 with TREAT-HF, has been used as an electrophilic fluorinating reagent for the first time to monofluorinate 1,3-ketoesters and difluorinate 1,3-diketones in good isolated yields.
Bifunctional chiral thioureas have been successfully used as organocatalysts in enantioselectivefluorinations of β-ketoesters. The corresponding products could be obtained with good to excellent enantioselectivity in high yields by using N-fluorobisbenzenesulphonimide (NFSI) as fluorination reagent.
Catalytic Enantioselective Fluorination of β-Keto Esters by Phase-Transfer Catalysis Using Chiral Quaternary Ammonium Salts
作者:Dae Young Kim、Eun Joo Park
DOI:10.1021/ol010281v
日期:2002.2.1
[reaction: see text] The catalyticenantioselective electrophilic fluorination promoted by quaternary ammonium salt from cinchonine as a phase-transfer catalyst is described. Treatment of beta-keto esters with N-fluorobenzenesulfonimide as the fluorine source under mild reaction conditions afforded the corresponding alpha-fluoro beta-keto esters in exellent yields with good to moderate enantiomeric
Activation of the hypervalent fluoroiodane reagent by hydrogen bonding to hexafluoroisopropanol
作者:Harsimran K. Minhas、William Riley、Alison M. Stuart、Martyna Urbonaite
DOI:10.1039/c8ob02236d
日期:——
Hexafluoroisopropan-2-ol (HFIP) is an excellent solvent for promoting fluorinations with the hypervalent fluoroiodane reagent 1 and crucially, it removes the need for transition metals or TREAT-HF activators. The fluoroiodane reagent 1 was used in HFIP to monofluorinate 1,3-ketoesters and to fluorocyclise unsaturated carboxylicacids in excellent yields under mild reaction conditions.