Enantioselective Friedel–Crafts Alkylation Reaction of Indoles with α-Trifluoromethylated β-Nitrostyrenes Catalyzed by Chiral BINOL Metal Phosphate
2019; American Chemical Society; Volume: 9; Issue: 8 Linguagem: Inglês
10.1021/acscatal.9b01811
ISSN2155-5435
AutoresIgnacio Ibáñez, Mio Kaneko, Yuto Kamei, Ryosuke Tsutsumi, Masahiro Yamanaka, Takahiko Akiyama,
Tópico(s)Chemical Synthesis and Reactions
ResumoAn efficient enantioselective Friedel–Crafts alkylation reaction of indoles with α-CF3-substituted β-nitrostyrenes is disclosed. The key to success is the use of a chiral calcium BINOL bis(phosphate) complex as a Lewis acid catalyst. The reaction gives access to a wide variety of optically active indoles bearing trifluoromethylated all-carbon quaternary stereocenter (up to 20 examples) in high yields (up to 99%) with excellent enantioselectivities (up to 98%) under mild reaction conditions. Nonactivated α-alkyl-β-nitrostyrenes also participated in the Friedel–Crafts alkylation reaction successfully.
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