Iron‐Catalyzed Intermolecular Azidabenzoyl Difluoromethylation of Alkenes to Access
β
‐Difluoroacyl Azides
摘要:
AbstractA Fe(II)‐catalyzed three‐component reaction of 2‐iodo‐2,2‐difluoroacetophenones, alkenes and TMSN3 is described, which provides a particularly valuable route to access difluoroalkylated azides with high yields. The method permits the efficient azidation of varied β‐difluoroacyl‐benzylic radicals in mild conditions with high functional group tolerance. Preliminary mechanistic investigation indicated that a radical‐mediated process was involved in this azidadifluoroacylation reaction.
Cu(I)‐catalyzed three‐component reaction of 2‐iodo‐2,2‐difluoroacetophenones, alkynes, and TMSCN for the synthesis of useful difluoroacyl‐substituted nitriles is described. This method has broad substrate scope and excellent stereoselectivity. Preliminary mechanistic investigation indicated that a radical‐mediated process was involved in this cyanodifluoroalkylation reaction.
A nickel-catalyzed aminofluoroalkylative cyclization of unactive alkenes with iododifluoromethyl ketones was developed to construct versatile difluoroalkylated Nitrogen-containing heterocycles including aziridines, pyrrolidines and piperidines in moderate to high yields. This method features a broad substrate scope and has been demonstrated on gram scale.
A visible light promoted C(sp3)–H difluoromethylation of tetrahydroisoquinolines that uses stable and easily prepared α,α-difluorinated gem-diol as the CF2 source is disclosed.
An efficient biocatalytic reduction of difluoroalkyl ketones for accessing chiral fluoroalkyl secondary alcohols is reported using commercial NADPH-dependent ketoreductase K234 with 2-propanol as a co-substrate for NADPH regeneration. This bioreduction reaction could be applied to a broad range of prochiral fluoroketones including aryl difluoroketones, aliphatic difluoroketones, and trifluoroacetophenones
据报道,使用商业 NADPH 依赖性酮还原酶 K234 和 2-丙醇作为 NADPH 再生的共底物,可有效生物催化还原二氟烷基酮以获得手性氟烷基仲醇。这种生物还原反应可应用于广泛的前手性氟酮,包括芳基二氟酮、脂肪族二氟酮和三氟苯乙酮,在高底物浓度(100 g L -1). 这些结果表明 K234 在工业生产有价值的手性氟代醇方面具有潜力。此外,该生物催化方案在不添加外部烟酰胺辅助因子的情况下也可以有效,这为酮还原酶 K234 在手性仲醇不对称合成中的进一步应用提供了有用的指导。