title: Pyridine core activation via 1,5-electrocyclization of vinyl pyridinium ylides generated from bromo isomerized Morita-Baylis-Hillman adduct of isatin and pyridine: synthesis of 3-spirodihydroindolizine oxindoles.
abstract: An activation of the pyridine nucleus has been achieved via 1,5-electrocyclization of vinyl pyridinium ylides generated from bromo isomerized Morita-Baylis-Hillman adducts of isatin and pyridine under basic conditions. The method has been successfully applied for an efficient synthesis of a number of 3-spirodihydroindolizine-2-oxindoles, which have been found as core structure of secoyohimbane and heteroyohimbane alkaloid natural products.
authors.affiliation: Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Trivandrum-695 019, Kerala, India.
authors.forename: Baby
authors.initials: B
authors.lastname: Viswambharan
authors.forename: Kodirajan
authors.initials: K
authors.lastname: Selvakumar
authors.forename: Suchithra
authors.initials: S
authors.lastname: Madhavan
authors.forename: Ponnusamy
authors.initials: P
authors.lastname: Shanmugam
mesh_terms: D003500:Cyclization; D004563:Electrochemistry / Q000379:methods*; D007211:Indoles / Q000737:chemistry*; D007510:Isatin / Q000737:chemistry*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D011725:Pyridines / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D007211:Indoles; D011725:Pyridines; D007510:Isatin; C023666:pyridine