In:
Chemistry – A European Journal, Wiley, Vol. 21, No. 23 ( 2015-06), p. 8351-8354
Abstract:
Two attractive chirons, aldehyde 6 and chloride 7 , exhibiting functionalized ent ‐spongiane‐type tricyclic skeletons (ABC ring system), have been constructed and their absolute configurations have been studied by NMR spectroscopy and confirmed by single‐crystal X‐ray diffraction. Both of these chirons are derived from commercially available andrographolide in good yield. Aldehyde 6 is obtained through a novel K 2 S 2 O 8 ‐catalyzed aquatic ring‐closing reaction of allylic sodium sulfonate and intramolecular 1,7‐hydrogen atom transfer process. Further mechanistic investigations demonstrate that the 1,7‐hydrogen atom transfer is a free‐radical process, whereby hydrogen migrates from C18 to C17, as evidenced by double‐18‐ deuterium‐labeled isotope experiments. Prospective applications of these two chiral sources are also discussed.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.201500794
Language:
English
Publisher:
Wiley
Publication Date:
2015
detail.hit.zdb_id:
1478547-X
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