Chiron approach for the synthesis of (5RS)-Hagen’s gland lactones from diacetone-d-mannose

Enantioselective Total Synthesis of (+)‐Hagen's Gland Lactones

“…An asymmetric version of this approach was subsequently reported by Gracza. [4] The bis-acetonide of mannofuranolactone was the chiral starting material in a synthesis outlined by Chakravarthy, [5] whereas Sartillo-Piscil used a 1,2-O-isopropylidene-α-d-xylofuranose derivative as the chiral synthon. [6] Yadav et al reported an elegant divergent approach to the formal synthesis of these lactones, which involved a base-mediated rearrangement of oxepanone epoxide.…”

Cyclisation of 1,2-dioxines containing tethered hydroxyl and carboxylic acid functionality: synthesis of tetrahydrofurans and dihydrofuran-2(3H)-ones

“…6 Hz between H a and H b and between H b and H c observed. Additionally ROESY 2D 1 H NMR of the obtained cis fused furans 11 showed interactions between the proton a to the X group and the methyl or phenyl functional groupings.…”

“…Such furans and lactones are at the cores of numerous natural products. 5,6 2. Results and discussion…”

Several Enantiopure Chiral Building Blocks Derived from D‐Mannose and a Formal Synthesis of Dubiusamine C

“…Thus, hydrolysis of the acetonide protecting group in 10 with 60% aq. AcOH [5] provided an intermediate triol. Regioselective protection of the primary hydroxyl group of the triol under the conventional t-BuCOCl/base (Et 3 N or pyridine) conditions led to a complex mixture, presumably due to intramolecular etherification of the hydroxyl groups.…”