title: Synthesis of annulated arenes and heteroarenes involving Lewis acid-mediated regioselective annulation of unsymmetrical 1,2-(diaryl/diheteroarylmethine)dipivalates.
abstract: A ZnBr(2)-mediated regioselective annulation of unsymmetrical 1,2-diarylmethinedipivalates in DCM at room temperature led to the formation of annulated arenes and heteroarenes. The annulation of the dipivalate proceeds through the intermediacy of benzylic carbocations followed by intramolecular cyclization and subsequent aromatization to give the annulated products. The annulation methodology is highly efficient for the syntheses of anthracene as well as naphtho[b]thiophene analogues.
authors.affiliation: Department of Organic Chemistry, School of Chemistry, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India.
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Sivasakthikumaran
authors.forename: Meganathan
authors.initials: M
authors.lastname: Nandakumar
authors.forename: Arasambattu K
authors.initials: AK
authors.lastname: Mohanakrishnan