Chiral Sulfonimide as a Brønsted Acid Organocatalyst for Asymmetric Friedel–Crafts Alkylation of Indoles with Imines
作者:Ling-Yan Chen、Hao He、Wing-Hong Chan、Albert W. M. Lee
DOI:10.1021/jo2011335
日期:2011.9.2
Binaphthyl-based chiral sulfonimide (CSI) is demonstrated for the first time to be an efficient, strong Brønsted acid in asymmetric organocatalysis. A series of CSIs were synthesized and screened in the asymmetric Friedel–Crafts alkylation of indoles with imines. Good to excellent yields and enantioselectivities have been achieved. It was proved that it was crucial to wash the CSI catalyst with HCl
Vanadium-mediated enantioselective FriedelâCrafts (FC)-type reactions were established using the dinuclear vanadium complex (Ra,S,S)-1a. The vanadium complex promoted the FC-type reaction of imines with 2-naphthols or indoles to give corresponding adducts with high enantioselectivities.
Dinuclear zinc catalyzed asymmetric Friedel–Crafts amidoalkylation of indoles with aryl aldimines
作者:Bei-Lei Wang、Nai-Kai Li、Jin-Xin Zhang、Guo-Gui Liu、Teng Liu、Qi Shen、Xing-Wang Wang
DOI:10.1039/c0ob01200a
日期:——
The asymmetric Friedel–Crafts amidoalkylation of indoles with aryl aldimines could be efficiently catalyzed by Trost's bis-ProPhenol dinuclear zinc complexes to attain 3-indolyl methanamine derivatives in good to excellent yields (85–98%) with moderate to high enantiomeric ratios (from 70 : 30 up to 95 : 5 er). Remarkably, this approach provides efficient access to enantiomerically enriched 3-indolyl
Squaramide-catalyzed enantioselective Friedel–Crafts reaction of indoles with imines
作者:Yong Qian、Gaoyuan Ma、Aifeng Lv、Hai-Liang Zhu、Jing Zhao、Viresh H. Rawal
DOI:10.1039/b922120d
日期:——
Chiral squaramides are highly enantioselective catalysts for FriedelâCrafts reaction of indoles with N-tosyl imines, affording 3-indolyl methanamine products in 85â96% yields and 84â96% ees.
Cool cats: 1,1′‐Bi‐2‐naphthol and vaulted 3,3′‐biphenanthrol‐type bisphosphorylimides enabled the atom‐economical and highlyenantioselective Friedel–Crafts reaction between indoles and N‐tosylimines with a low catalyst loading (see scheme). A very small amount of 4‐(dimethylamino)pyridine (DMAP) suppressed the bisindole side product efficiently. The ortho‐substituted aldimine substrates performed