Rapid route to 3,4-substituted indoles via a directed ortho metalation-retro-Mannich sequence.
[reaction: see text] In the presence of NXS (X = Br, I, Cl), gramine derivatives 1, derived by combined directed ortho metalation (DoM)-cross-coupling sequences, rapidly undergo retro-Mannich fragmentation (2) to afford 3-halo indoles 3 in 37-88% yields. A conceptually new methodology to diverse 3,4-substituted indoles (10, 11, 13) is thereby introduced.
Chauder
Brian
B
Department of Chemistry, Queen's University, Kingston, ON, K7L 3N6, Canada.
Larkin
Andrew
A
Snieckus
Victor
V
D000470:Alkaloids / Q000138:chemical synthesis / Q000737:chemistry; D006219:Halogens / Q000737:chemistry; D026121:Indole Alkaloids; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry
D000470:Alkaloids; D006219:Halogens; D026121:Indole Alkaloids; D007211:Indoles; C007884:gramine