Blue-light-induced The Cyclopropanation Of Indoles With Aryldiazoacetates

In this dissertation,blue light-mediated cyclopropanation of indoles with aryldiazoacetates have been developed.In the air atmosphere,the cyclopropanation of indoles with aryldiazoacetates delivered the cyclopropane-fused indolines products under the irradiation of blue light.Notably,operational simplicity,atom efficiency and eco-friendly energy source are the salient features of this strategy.In this protocol,there is no need for transition metal catalyst and blue light was employed as the sole requirement for the transformation,which correspond with the eco-friendly idea.Additionally,this reaction system could tolerate various functional group such as methyl,methoxy,halogen,nitro,ester,nitrile,etc.A variety of cyclopropane-fused indoline compounds were obtained in moderate to excellent yields and high diastereoselectivities under milder conditions(31 examples,up to 98% yield,dr > 20:1).According to the related literature and discussion of experimental results,the possible mechanism of the reaction is proposed.The main research contents are as follows: 1.Synthesis of N-pivaloylindole and aryldiazoacetates compounds containing various substituents(a)N-pivaloylindole: The pivaloyl chloride and the indole containing different substituents can be efficiently converted to N-pivaloylindole via DMAP condensation.(b)Aryldiazoacetates compounds: First,acetamidobenzenesulfonyl chloride and sodium azide can be efficiently converted to p-acetamidobenzenesulfonyl azide with acetone/water as solvent.Then acetonitrile was used as a solvent and under the action of DBU,acetamidobenzenesulfonyl azide and the substituted methyl phenylacetate can be efficiently transformed to the aryldiazoacetates compounds.2.Blue light-mediated cyclopropanation of indoles The reaction was carried out by using N-pivaloylindole 1a as a model reaction substrate and aryldiazoacetate 2a as a cyclopropanation reagent.The optimal reactio n conditions were: 1a(1 equive),2a(2 equive),1 ml of dichloromethane as the reaction solvent,blue LEDs light as light source,and reacting at room temperature for 6 hours.Under the optimal reaction conditions,the universality of N-pivaloylindole and aryldiazoacetate substrates was investigated,affording the products with 63%-98% yields,dr > 20:1.Finally,according to the related literature and experimental results,a possible mechanism of the reaction was proposed.