Title: One-pot synthesis of highly substituted N-fused heteroaromatic bicycles from azole aldehydes.
Authors: Outlaw, Victor K; d'Andrea, Felipe B; Townsend, Craig A
Published In Org Lett, (2015 Apr 17)
Abstract: An efficient route to substituted N-fused aromatic heterocycles, including indolizines, imidazo[1,2-a]pyridines, and imidazo[1,5-a]pyridines from azole aldehydes, is reported. Wittig olefination of the aldehydes with fumaronitrile and triethylphosphine affords predominantly E-alkenes that undergo rapid cyclization upon treatment with a mild base. Substituent control of the 1-, 2-, and 3-positions of the resulting heteroaromatic bicycles is shown. Alternatively, the isolable E-alkene undergoes selective alkylation with electrophiles, followed by in situ annulation to indolizines additionally substituted at the 6-position.
PubMed ID: 25815402
MeSH Terms: Indolizines/chemical synthesis*; Indolizines/chemistry; Molecular Structure; Pyridines/chemical synthesis*; Pyridines/chemistry; Stereoisomerism