Selective C–O bond formation via a photocatalytic radical coupling strategy: access to perfluoroalkoxylated (OR_F) arenes and heteroarenes

Abstract

Synthesis of perfluoroalkoxylated (hetero)arenes (Ar–ORF) from readily available perfluoroalkyl iodides (RF–I) through photocatalytic selective O–RF bond formation.

Nucleophilic and Radical Heptafluoroisopropoxylation with Redox‐Active Reagents

“…Normally,h eptafluoroisopropyl ethers were prepared through nucleophilic substitution reactions with the in situ generated heptafluoroisopropoxide anion from hexafluoroacetone and metal fluoride (Scheme 1a), [10] but the reaction was limited by the usage of the gaseous and highly toxic hexafluoroacetone.V ery recently,Ngai reported the synthesis of heptafluoroisopropyl aryl ethers through ap hotocatalytic heptafluoroisopropylation of N-aryl-N-hydroxylamides with ICF(CF 3 ) 2 followed by an intramolecular OCF(CF 3 ) 2 migration (Scheme 1b), [11] and Hu described one example of the heptafluoroisopropoxylation-bromination of the in situ generated aryne with BzOCF(CF 3 ) 2 prepared from hexafluoroacetone (Scheme 1c). [12] Obviously,t he substrate scope of these two synthetic methods was rather narrow.T herefore, the development of new reagents and reactions for the preparation of heptafluoroisopropyl ethers is of high demand.…”

Advances in the Development of Trifluoromethoxylation Reagents

“…Photocatalytic procedure under optimized conditions was applicable to aromatic hydroxylamides 25 bearing such functional groups as tert-butyl, bromo, esters and carbamates with yield ranging from 45% to 66%. Photocatalytic procedure using N-aryl-N-hydroxylamides 27 (Scheme 23) and commercially available trifluoromethyl iodide instead of expensive Togni reagents to access a range of aryl trifluoromethyl ethers 3 was recently developed [99,100]. In this transformation, Ru(bpy) 3 (PF 6 ) 2 was used as a photoredox catalyst in the presence of potassium carbonate as a base in acetonitrile upon irradiation with blue LED light.…”

“…mercially available trifluoromethyl iodide instead of expensive Togni reagents to access a range of aryl trifluoromethyl ethers 3 was recently developed [99,100]. In this transformation, Ru(bpy)3(PF6)2 was used as a photoredox catalyst in the presence of potassium carbonate as a base in acetonitrile upon irradiation with blue LED light.…”

Design and Reaction of Nucleophilic and Radical Heptafluoroisopropoxylation Reagents

“…一般的合成方法是使用金属氟盐与六氟 丙酮反应原位生成七氟异丙氧基负离子 [6] , 随之发生亲 核取代反应生成七氟异丙基醚类化合物, 但该方法受限 于气态且剧毒的六氟丙酮的使用. 最近, Ngai 课题组 [7] 报道了 N-芳基-N-羟基酰胺化合物与 ICF(CF 3 ) 2 作用, 得…”