Stereoselective syntheses of dihydroxerulin and xerulinic acid, anti-hypocholesterolemic dyes from the fungus Xerula melanotricha.
The title compounds 2 and 3, which are inhibitors of the biosynthesis of cholesterol, were synthesized in a convergent and perfectly stereoselective manner. In the key step, bromobutenolide 6 (obtained from levulinic acid in two steps) was coupled with either of the novel bis(stannanes) trans,cis,trans-35 or trans,trans,trans-35 [each accessible from 3-(tributylstannyl)allyl alcohol (17) in four steps], giving gamma-alkylidenebutenolide trans,trans,trans-32. This compound was coupled with iododiyne 42 or the bromoenediynoate 44 leading to dihydroxerulin (2) and to the (trimethylsilylethyl)ester 45 of xerulinic acid, respectively. Deprotection of the latter provided totally synthetic xerulinic acid (3) for the first time.
Sorg
Achim
A
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstrasse 21, 79104 Freiburg, Germany.
Siegel
Konrad
K
Brückner
Reinhard
R
D000363:Agaricales / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry; D053280:Diynes; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism; D017971:Tin Compounds / Q000737:chemistry
D000480:Alkynes; D053280:Diynes; D007783:Lactones; D017971:Tin Compounds; C066798:dihydroxerulin; C066800:xerulinic acid; C031525:stannane