Asymmetric Friedel-Crafts reaction of 4,7-dihydroindoles with nitroolefins by chiral Brønsted acids under low catalyst loading.
Slowly does it! By adding the substrate by a syringe pump, a highly efficient Friedel-Crafts reaction of 4,7-dihydroindoles with nitroolefins was realized with 0.5 mol % of a chiral phosphoric acid. The Friedel-Crafts alkylation, together with a subsequent oxidation of the product, led to 2-substituted indoles in excellent enantiomeric excesses, which can be easily transformed to enantioenriched tetrahydro-gamma-carbolines.
Sheng
Yi-Fei
YF
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 54 Fenglin Lu, Shanghai, China.
Li
Gong-Qiang
GQ
Kang
Qiang
Q
Zhang
An-Jiang
AJ
You
Shu-Li
SL
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D007211:Indoles / Q000737:chemistry*; D010756:Phosphoric Acids / Q000737:chemistry; D013237:Stereoisomerism
D000475:Alkenes; D007211:Indoles; D010756:Phosphoric Acids; C030242:phosphoric acid