Study On Baeyer-villiger Oxidation Of Cyclone With Chiral Ionic Catalyst

Cyclolactones are an important class of intermediates.Baeyer-Villiger oxidation reactions are commonly used in chemistry and chemical production to synthesize cyclic lactones.The use of peroxyacid as an oxidant is costly and polluting.When using O₂ as an oxidant,an additional co-oxidant is required.Usually,an aldehyde is used as a co-oxidant.In this paper,three types of chiral ionic catalysts were prepared.The structural characterization and thermal stability analysis of the ionic catalysts were carried out by different means,and then the Baeyer-Villiger oxidation reaction of cyclic ketones was studied.The three types of catalytic systems in this paper are as follows:?1?Baeyer-Villiger oxidation of cyclic ketones catalyzed by chiral alcohol ionic catalysts:Chiral alcohols?L-menthol,S-?-?-2-methyl-1-butanol,?-tropinol,?S?-?-?-1-phenylethanol?as a chiral center were respectively introduced into the cation of N-n-butylimidazolium,and the acid radical of Br?nsted acid(H₃PW₁₂O₄₀,H₃PMo₁₂O₄₀,H₄SiW₁₂O₄₀,CF₃SO₃H,H₂SO₄)was anion.A series of chiral alcohol ionic catalysts were designed and synthesized,and used to catalyze Baeyer-Villiger oxidation reaction of various cyclic ketones.Using 2-heptylcyclopentanone as a model substrate,acatalyst[?S?-?-?-2-MBE-Nimi-H]H₂PW₁₂O₄₀with?S?-?-?-2-methyl-1-butanol as the chiral center was selected as the optimal catalyst,and the optimal reaction conditions are optimized.At n?2-heptylcyclopentanone?=5 mmol,n([?S?-?-?-2-MBE-Nimi-H]H₂PW₁₂O₄₀)=0.3 mmol,n?H₂O₂?=5 equiv,T=60 ^oC,t=6 h,the conversion of 2-heptylcyclopentanone was 83.17%,and the yield of?-dodecarolactone was 48.29%,and the selectivity of the reaction was 58.06%.The chiral alcohol ionic catalyst was recycled,and the catalyst could be recycled and used4 times.In addition,the catalyst[?S?-?-?-2-MBE-Nimi-H]H₂PW₁₂O₄₀ could also catalyze the Baeyer-Villiger oxidation reaction of other cyclic ketones,and had a higher lactone selectivity.?2?Baeyer-Villiger oxidation of cyclic ketones catalyzed by amino acid ionic catalysts:By the reaction of different natural L-configuration amino acids?L-valine,L-leucine,L-lysine,etc.?with different Br?nsted acid,a series of amino acid ionic catalysts were designed and synthesized,and used to catalyze the Baeyer-Villiger oxidation reaction of different cyclic ketones.With 2-heptylcyclopentanone as the model substrate,the proline catalyst[Pro-H]H₂PW₁₂O₄₀ was selected as the optimal catalyst,and the optimal reaction conditions were optimized.At n?2-heptylcyclopentanone?=5 mmol,n([Pro-H]H₂PW₁₂O₄₀)=0.2 mmol,n?H₂O₂?=3.5 equiv,T=60 ^oC,t=6 h,the conversion of 2-heptylcyclopentanone was 97.22%.The yield of?-dodecyllactone was 80.04%,and the selectivity of the reaction was82.33%.The amino acid ionic catalyst was recycled,and the catalyst could be recycled and used 5 times.In addition,the catalyst[Pro-H]H₂PW₁₂O₄₀ had high catalytic activity for Baeyer-Villiger oxidation of other cyclic ketones.?3?Baeyer-Villiger oxidation of cyclic ketone catalyzed by chiral amine/amide type ionic catalysts:By using natural nitrogen-containing compound as chiral center,and reacting with Br?nsted acid(H₃PW₁₂O₄₀,H₃PMo₁₂O₄₀,H₄SiW₁₂O₄₀,CF₃SO₃H,H₂SO₄),a series of chiral amine/amide catalysts were prepared and used to catalyze Baeyer-Villiger oxidation of different cyclic ketones.With 2-heptylcyclopentanone as the model substrate,the catalyst[A-H][H₂SO₄]₂ with D-diethyl tartrate as the chiral center was selected as the optimal catalyst,and the optimal reaction conditions were optimized.At 2-heptylcyclopentanone=5 mmol,n?[A-H][H₂SO₄]₂?=0.45 mmol,n?H₂O₂?=3 equiv,T=50 ^oC,t=9 h,the conversion of heptylcyclopentanone was83.17%,the yield of?-dodecyllactone was 48.29%,and the selectivity of the reaction was 58.06%.The amine/amide type ionic catalyst was recycled,and the catalyst could be recycled and used 4 times.In addition,the catalyst[A-H][H₂SO₄]₂ could also catalyze the Baeyer-Villiger oxidation reaction of other cyclic ketones.In the three types of chiral ionic catalysts for the Baeyer-Villiger oxidation reaction system of cyclic ketones,the amino acid-based ionic catalysts show the best catalytic activity and universality of substrates because of their moderate acidity and oxidizationThis thesis lays a certain foundation for the subsequent research on asymmetric Baeyer-Villiger catalytic oxidation reaction.