title: Synthesis of benzofurans via an acid catalysed transacetalisation/Fries-type O → C rearrangement/Michael addition/ring-opening aromatisation cascade of β-pyrones.
abstract: An unusual and facile approach for the synthesis of 2-benzofuranyl-3-hydroxyacetones from 6-acetoxy-β-pyrones and phenols is presented. The synthetic sequence involves a cascade transacetalisation, Fries-type O → C rearrangement followed by Michael addition and ring-opening aromatisation. The versatility of this method was further demonstrated via the synthesis of 4,4a-dihydropyrano[3,2-b]benzofuran-3-ones, furo[3,2-c]coumarins, and spiro[benzofuran-2,2'-furan]-4'-ones. The unexpected cascade event would also provide new possible considerations in the β-pyrone-involved organic synthesis.
authors.affiliation: Organic Synthesis and Catalysis Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, S. A. S. Nagar, Manuali PO, Punjab 140306, India. ramsastry@iisermohali.ac.in ramsastrys@gmail.com.
authors.forename: Siddheshwar K
authors.initials: SK
authors.lastname: Bankar
authors.affiliation: Organic Synthesis and Catalysis Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, S. A. S. Nagar, Manuali PO, Punjab 140306, India. ramsastry@iisermohali.ac.in ramsastrys@gmail.com.
authors.forename: Jopaul
authors.initials: J
authors.lastname: Mathew
authors.affiliation: Organic Synthesis and Catalysis Lab, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge City, Sector 81, S. A. S. Nagar, Manuali PO, Punjab 140306, India. ramsastry@iisermohali.ac.in ramsastrys@gmail.com.
authors.forename: S S V
authors.initials: SS
authors.lastname: Ramasastry