title: Asymmetric Roadmap to Diverse Polycyclic Benzopyrans via Phosphine-Catalyzed Enantioselective [4 + 2]-Annulation Reaction.
abstract: The catalytic addition of the amino acid derived bifunctional N-acylaminophosphine to an α-substituted allene ester generated a zwitterionic dipole that engaged the vinylogous ester function of 3-cyano-chromones in a [4 + 2] annulation reaction to deliver tetrahydroxanthones embodying three consecutive chiral centers in high yields and with excellent enantioselectivities. The established asymmetric synthesis further paves the way to two different classes of complex, sp(3)-rich tetracyclic benzopyrans via efficient cascade reactions.
authors.affiliation: Max-Planck-Institut für Molekulare Physiologie , Abteilung Chemische Biologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.|Fakultät Chemie und Chemische Biologie, Technische Universität Dortmund , Otto-Hahn-Straße 6, 44221 Dortmund, Germany.
authors.forename: Adithi
authors.initials: A
authors.lastname: Danda
authors.affiliation: Max-Planck-Institut für Molekulare Physiologie , Abteilung Chemische Biologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.
authors.forename: Naredla
authors.initials: N
authors.lastname: Kesava-Reddy
authors.affiliation: Fakultät Chemie und Chemische Biologie, Technische Universität Dortmund , Otto-Hahn-Straße 6, 44221 Dortmund, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Golz
authors.affiliation: Fakultät Chemie und Chemische Biologie, Technische Universität Dortmund , Otto-Hahn-Straße 6, 44221 Dortmund, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Strohmann
authors.affiliation: Max-Planck-Institut für Molekulare Physiologie , Abteilung Chemische Biologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.
authors.forename: Kamal
authors.initials: K
authors.lastname: Kumar