title: [4 + 2] Benzannulation of 3-Alkenylpyrroles/Thiophenes with Propargylic Alcohols: Access to Substituted Indoles, Benzothiophenes, and Aza[5]helicenes.
abstract: An efficient and practical one-pot [4 + 2] benzannulation method to produce highly substituted indoles and 1-benzothiophenes via sequential acid-catalyzed propargylation/base-mediated cycloisomerization reactions has been developed. This method allows access to differently substituted (mainly on phenyl ring) indoles and 1-benzothiophenes from the reaction of 3-alkenylpyrroles/-thiophenes as C4 synthons with 1-aryl/1-heteroaryl propargylic alcohols as C2 synthons. Interestingly, dialkynyl substrates can undergo tandem benzannulations to give substituted aza[5]helicenes in 82-83% yield.
authors.affiliation: Division of Natural Products Chemistry, CSIR-Indian Institute of Chemical Technology Hyderabad 500607, India.|Academy of Scientific and Innovative Research , New Delhi, India.
authors.forename: Chada
authors.identifier: 0000-0003-1491-7381
authors.initials: C
authors.lastname: Raji Reddy
authors.affiliation: Division of Natural Products Chemistry, CSIR-Indian Institute of Chemical Technology Hyderabad 500607, India.
authors.forename: Reddi
authors.initials: R
authors.lastname: Rani Valleti
authors.affiliation: Division of Natural Products Chemistry, CSIR-Indian Institute of Chemical Technology Hyderabad 500607, India.|Academy of Scientific and Innovative Research , New Delhi, India.
authors.forename: Puppala
authors.initials: P
authors.lastname: Sathish