Research On α-C(sp~3)-H Addition Reaction Of Cyclopropanes With Alkenes By Organo-Rare-Earth Complexes

Cyclopropane compounds,due to their unique spatial,electronic and conformational characteristics,have become attractive pharmacodynamic groups in medicinal chemistry,effective intermediates in synthetic chemistry and efficient ligands in catalysis,and how to simply and efficiently synthesize cyclopropane and its derivatives has been one of the research hotspots.Cypopropane C-（sp³）-H bond hydrocarbon activation is one of the effective methods for synthesize cypopropane derivatives.In recent years,cyclopropane C-（sp³）-H hydrocarbon activation has been greatly developed,however,cypopropane catalyzed C-（sp³）-H hydrocarbon activation catalyzed by organic rare earth has been rarely been reported.Compared to the transition metals,the organic rare-earth-catalyzed hydrocarbon activation reactions can significantly improve the atomic utilization efficiency,with simple reaction conditions and more in line with the concept of green chemistry.Recently,our research group found for the first time that monophosphonamine rare earth compounds can catalyze the addition reaction of the C-（sp³）-H bond of cyclopropane and olefin,which was conducted in place.The specific study is as follows:（1）Synthesisofmonophosphamiderareearthcompounds（η²-N-P）Ln（CH₂C₆H₄NMe₂-o）₂（NP-Ln）（Ln=Sc,Y,Lu,Ga）and monomolar rare earth compounds（η⁵:-C₅Me₄-C₅H₃NMe-o）Ln（CH₂Si Me₃）₂（THF）_n(Cp ^N-Me-Ln)（Ln-Sc,Y,Lu）replaced by pyridine groups,and their structure was characterized by nuclear magnetic and single-crystal diffraction methods.（2）The catalytic system of NP-Ln/Cp ^N-Me-Lnwas constructed,the best conditions for the reaction are:the reaction solvent is chlorobenzene,the catalyst and auxiliary catalyst（1:1）is 4.0 mmol%,The ratio of cyclopropanes to olefin is 1:4,and the reaction temperature is 100℃.（3）The alkylation reaction of the cyclopropane compounds C-（sp³）-H bond with the alkene was studied with NP1-Y as the catalyst and[Ph³C][B（C₆F₅）₄]as the auxiliary catalyst.The olefin substrate was expanded with the 2-cyclopropyl-6-ethyl-pyridine as the substrate.The 2-Cyclopropyl-6-ethyl-pyridine activates the C-（sp³）-H bond with various olefin species,and the yield of the addition product is 61-93%.（4）The alkylation reaction of the cyclopropane compounds C-（sp³）-H bond with theα-alkene was studied with NP1-Y as the catalyst and[Ph³C][B（C₆F₅）₄]as the auxiliary catalyst.The cyclopropane substrate was expanded with the 1-octylene as the substrate.The 1-octylene activates the C-（sp³）-H bond with various Cyclopropane compound species,and the yield of the addition product is 61-93%.（5）The alkylation reaction of the cyclopropane compounds C-（sp³）-H bond with the alkene was studied with NP1-Y as the catalyst and[Ph³C][B（C₆F₅）₄]as the auxiliary catalyst.The cyclopropane substrate was expanded with the styrene as the substrate.The styrene activates the C-（sp³）-H bond with various Cyclopropane compound species,and the yield of the addition product is 61-78%.