title: Experimental and computational exploration of indolizinyl carbene generation. A route to biindolizines.
abstract: In previous work, (E)-2-enynyl pyridines were reported to yield indolizinyl singlet carbenes through base-catalyzed E/Z isomerization followed by a 5-exo-dig pseudocoarctate cyclization. We report herein that in the presence of ethyl acrylate these carbenes undergo stereoselective cis-cyclopropanation due mainly to electrostatic interactions in the transition state. The scope of this carbene generation scheme has been further explored through the preparation of a symmetric bis(pyridylenyl)alkyne which spontaneously furnished the biindolizine core in a one-pot reaction. Computational characterization of this transformation suggests a highly asynchronous double cyclization.
authors: Departamento de Química Orgánica, Universidade de Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain.
authors: Inmaculada R
authors: IR
authors: Lahoz
authors: Carlos Silva
authors: CS
authors: López
authors: Armando
authors: A
authors: Navarro-Vázquez
authors: María-Magdalena
authors: MM
authors: Cid
mesh_terms: D003500:Cyclization; D003521:Cyclopropanes / Q000737:chemistry; D007212:Indolizines / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D011725:Pyridines / Q000737:chemistry; D011789:Quantum Theory; D013696:Temperature
chemical_list: D003521:Cyclopropanes; D007212:Indolizines; D011725:Pyridines; C030011:carbene; C035094:indolizine; C030797:cyclopropane; D008697:Methane