BINAM and H8-BINAM-based chiral imines and Zn(OTf)2-catalyzed enantioselective Friedel–Crafts alkylation of indoles with nitroalkenes

Axially chiral imine ligands derived from (R)-BINAM are effective chiral ligands in the Zn(OTf)2-promoted enantioselective Friedel–Crafts alkylation of indoles with nitroalkenes under mild conditions to give the corresponding adducts in good yields and moderate enantioselectivities.

Axially chiral imine ligands derived from (R)-BINAM are effective chiral ligands in Zn(OTf)2-promoted enantioselective Friedel–Crafts alkylation of indoles with nitroalkenes under mild conditions to give the corresponding adducts in good yields and moderate enantioselectivities.Figure optionsDownload as PowerPoint slide

(R)-(+)-N,N′-Bis(2,3-dichlorobenzylidene)-1,1′-binaphthyl-2,2′-diamineC34H20Cl4N2Ee = 100%[α]D20=+217.5 (c 0.50, CH2Cl2)Source of chirality: resolutionAbsolute configuration: (R)

(R)-(+)-N,N′-Bis(2,4-dichlorobenzylidene)-1,1′-binaphthyl-2,2′-diamineC34H20Cl4N2Ee = 100%[α]D20=+140.5 (c 0.50, CH2Cl2)Source of chirality: optical resolutionAbsolute configuration: (R)

(R)-(+)-N-(2,3-Dichlorobenzylidene)-1,1′-binaphthyl-2,2′-diamineC27H18Cl2N2Ee = 100%[α]D20=+117.7 (c 0.50, CH2Cl2)Source of chirality: resolutionAbsolute configuration: (R)

(R)-(+)-N,N′-Bis(2-chlorobenzylidene)-3,3′-diphenyl-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl-2,2′-diamineC46H38Cl2N2Ee = 100%[α]D20=+3.8 (c 0.35, CH2Cl2)Source of chirality: resolutionAbsolute configuration: (R)