Application of iridium catalyzed allylic substitution reactions in the synthesis of branched tryptamines and homologues via tandem hydroformylation-Fischer indole synthesis.
Combination of enantioselective allylation reactions with a tandem hydroformylation-Fischer indole synthesis sequence as a highly diversity-oriented strategy for the synthesis of tryptamines and homologues was explored. This modular approach allows the substituents at C3 of the indole core, the type of the amine moiety, and the distance of the amine moiety to the indole core in the final synthetic step to be defined. The starting materials required for the hydroformylation step were synthesized via iridium catalyzed enantioselective allylic substitution reactions in high yields and excellent enantioselectivities. The Rh catalyzed hydroformylation step in the presence of phenyl hydrazine, allows the in situ formed aldehyde to be trapped as the hydrazone. Subsequent acid catalyzed indolization furnishes the desired indole structures in moderate to good yields.
Technische Universität Dortmund, Fachbereich Chemie, Organische Chemie I, Otto-Hahn-Str. 6, 44227 Dortmund.
Bojan P
BP
Bondzic
Andreas
A
Farwick
Jens
J
Liebich
Peter
P
Eilbracht
D000475:Alkenes / Q000737:chemistry; D000478:Alkylation; D002384:Catalysis; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D007495:Iridium / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D014363:Tryptamines / Q000138:chemical synthesis* / Q000737:chemistry
D000475:Alkenes; D007211:Indoles; D014363:Tryptamines; D007495:Iridium; C030374:indole