title: Asymmetric Total Syntheses of (-)-Hedycoropyrans A and B.
abstract: The first and asymmetric total synthesis of (-)-hedycoropyrans A (1) was accomplished in 18 steps with 5.4% overall yield. The key features of our strategy include (1) construction of the unusual trans-2-aryl-6-alkyl tetrahydropyran core via Achmatowicz rearrangement, Zn-mediated reductive deoxygenation, and Heck-Matsuda coupling reaction, and (2) installation of 3,4-anti-dihydroxy from the corresponding 3,4-syn-dihydroxy THP through chemo- and regioselective IBX oxidation and Evans-Saksena reduction. In addition, C2 epimerization of (-)-hedycoropyan A (1) under the acidic condition furnished (-)-hedycoropyan B (2) with 71% yield. This finding might suggest the biogenetic origin of hedycoropyran B.
authors.affiliation: Department of Chemistry, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Zhilong
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Chemistry, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong, China.|HKUST Shenzhen Research Institute , Shenzhen 518057, China.
authors.forename: Rongbiao
authors.identifier: 0000-0002-2740-5222
authors.initials: R
authors.lastname: Tong