Catalytic Asymmetric C-7 Friedel-Crafts Alkylation/N-Hemiacetalization of 4-Aminoindoles.

A unique catalytic asymmetric C-7 Friedel-Crafts alkylation/N-hemiacetalization cascade reaction of 4-aminoindoles with β,γ-unsaturated α-keto esters has been described. Using a chiral magnesium H8-BINOL-derived bis(phosphate) complex as catalyst, the resulting functionalized 1,7-annulated indole scaffolds are obtained in high yields (up to 98%) and with good to excellent enantioselectivities (up to 99%) and diastereoselectivities (up to >20:1) under mild reaction conditions.