Oxy-Difluoroalkylation of Allylamines with CO₂ via Visible-Light Photoredox Catalysis

Abstract

A selective oxy-difluoroalkylation of allylamines with carbon dioxide (CO) via visible-light photoredox catalysis is reported. These multicomponent reactions are efficient and environmentally friendly to generate a series of important 2-oxazolidinones with functionalized difluoroalkyl groups. The good functional group tolerance, broad substrate scope, easy scalability, mild reaction conditions, and facile functionalization of products provide great potential for application in organic synthesis and pharmaceutical chemistry.

Recent Advances in the Chemical Fixation of Carbon Dioxide: A Green Route to Carbonylated Heterocycle Synthesis

“…The reactions had three components and also involved alkyl halides and the presence of light, because generally the alkyl halide is homolitically broken by an irradiated metal catalyst. For instance tris(bipyridine)ruthenium(II) chloride allowed the synthesis of many oxazolidinones (Scheme 18, Equation (1)), as well as 3-benzyl-6-phenyl-6-(2,2-difluoro-3-ethoxy-3-oxopropyl)-1,3-oxazinan2-one and 3-benzyl-6-phenyl-5-(2,2difluoro-3-ethoxy-3-oxopropyl)-1,3-oxazinan-2-one (54 and 38% yields, respectively) [169]. The reaction of primary allylamines, allylamines with electron withdrawing nitrogen protecting groups or aliphatic R 2 substituents failed as well as the synthesis of cyclic carbonates from allyl alcohols and of oxazinone from 2-(prop-1-en-2-yl)aniline.…”

Synthesis of Oxazolidin‐2‐ones from Unsaturated Amines with CO2 by Using Homogeneous Catalysis

“…Recently,Y u 'sg roup reported an oxy-difluoroalkylation reaction of allylamines with CO 2 that was promoted by photoredox catalysis. [50] This three-component reaction afforded variousimportant difluoroalkylated 2-oxazolidones with broad substrate scope. Reductiveq uenching of the excited Ru II *p hotocatalyst by DABCO generated aR u I species, which reduced BrCF 2 COOEt into the CCF 2 COOEt radical.…”

Photocatalytic Difluoromethylation Reactions of Aromatic Compounds and Aliphatic Multiple C–C Bonds

“…The scope employing allylamines is illustrated in Scheme 32. The authors in [79] advanced a proposal for the realization of the mechanism, as depicted in Scheme 33. Based on mechanistic probe studies, a proposed reductive quenching of excited photocatalyst by DABCO (Ep ox = + 0.69 V vs. SCE, E[Ru(II)*/Ru(I)] = + 0.77 V) provides Ru(I), which reduces BrCF2COOEt to generate the CF2COOEt radical.…”

“…The scope employing allylamines is illustrated in Scheme 32. Yin, Yu, and colleagues [79] achieved the oxy-difluoroalkylation of allylamines with CO2 via visible-light photoredox catalysis to generate a series of relevant 2-oxazolidinones with functionalized difluoroalkyl groups employing BrCF2CO2Et as the source of radicals, Ru(bpy)3.Cl2.6H2O as the photocatalyst, DABCO as the base, DMF as the solvent, and irradiated with a blue LED. The scope employing allylamines is illustrated in Scheme 32.…”