title: One-pot synthesis of highly substituted N-fused heteroaromatic bicycles from azole aldehydes.
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.
authors: Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
authors: Victor K
authors: VK
authors: Outlaw
authors: Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
authors: Felipe B
authors: FB
authors: d'Andrea
authors: Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
authors: Craig A
authors: CA
authors: Townsend
mesh_terms: D007212:Indolizines / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D007212:Indolizines; D011725:Pyridines; C554655:imidazo(1,5-a)pyridine; C001439:imidazo(1,2-a)pyridine