| The bis?3-indolyl?methane?3,3?-BIM?is an important class of heterocycle compound,in which two 3-indolyl units are joined together by a simple or a substituted methylene bridge.It is found that 3,3?-BIM has important application value in biochemistry,pharmaceutical chemistry,material science and other fields.For example,the 3,3?-bis?3-indolyl?methane compounds have a versatile biological functions:inhibiting cancer cell growth,antiinflammatory,antifungal,regulating cell growth and differentiation.On the other hand,trifluoromethyl group can effectively enhance and modify metabolic stability,lipophilicity,and membrane permeability of the parent molecules due to its strong electron-withdrawing effect.Therefore,exploiting a direct and efficient strategy for the preparation of chiral trifluoromethylated bis?3-indolyl?methanes would be highly valuable.According to previous work,we developed the Ni?II?-?imidazoline-oxazoline?complex mediated highlystereoselectiveAF-CAreactionofindoleswith?-CF3-?-?3-indolyl?nitroalkenes,affording a series of chiral bis?3-indolyl?methanes bearing a trifluoromethylated all-carbon quaternary stereocenter in generally good yields with excellent enantioselectivities?up to 98%yield and 94%ee?.In addition,both enantiomers of a given trifluoromethylated 3,3?-BIM were obtained with high ee via removal of the indole N-protection group in the F-C products.The main contents are as follows:Asymmetric Friedel-Crafts alkylation reaction of indoles with nitroalkenesAsymmetric Friedel-Crafts reaction of indoles?0.3 mmol?and?-CF3-?-?3-indolyl?nitroalkenes?0.2 mmol?with was investigated.In the presence of6 mol%L1,5 mol%Ni?Cl O4?2·6H2O catalyst loading,toluene?2.0 m L?as solvent at70 oC for 24-62 h,36 optically active trifluoromethylated 3,3?-BIMs were successfully prepared in good yields with generally high enantioselectivity.Both the enantiomers of the given 3,3?-BIM were obtained via removal of the indole N-protection group in the F-C products. |
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