Highly enantioselective halocyclization reactions of indole derivatives, including
tryptophols and tryptamines, have been accomplished by means of anionic chiral Co(III)
complexes and 1,3-dihalohydantoins (as little as 0.50 equiv). 3-Halo-fused indolines
were obtained in excellent yields (up to 98%) and enantioselectivities (up to 98%
ee), employing the chiral anion phase-transfer-catalysis strategy.
Key words
anion phase-transfer catalysis - chiral Co(III) complex - Brønsted acid - indole derivatives
- halocyclization