Enantioselective synthesis of the dimeric pyranonaphthoquinone core of the cardinalins using a late-stage homocoupling strategy.
The enantioselective synthesis of a dimeric pyranonaphthoquinone closely related to the cardinalins is described. Whilst attempts to effect a double Hauser-Kraus annulation of enone 5 were unsuccessful using both bis-phthalide 4 and bis-sulfone 21, a single annulation of cyanophthalide 28 with enone 5 furnished functionalised naphthalene 31. Suzuki-Miyaura homocoupling of the aryl triflate 29 derived from 31 effected a late-stage construction of the biaryl bond and facilitated access to the biaryl 3. Double stereoselective lactol reduction installed the 1,3-cis stereochemistry of the pyran rings and a final double oxidative demethylation step furnished model dimer 1, completing the enantioselective synthesis of a dimeric pyranonaphthoquinone bearing the core structure of cardinalin 3.
Sperry
Jonathan
J
Department of Chemistry, University of Auckland, 23 Symonds Street, Auckland, New Zealand.
Gibson
Jennifer S
JS
Sejberg
Jimmy J P
JJ
Brimble
Margaret A
MA
D016227:Benzoquinones / Q000737:chemistry*; D019281:Dimerization; D009285:Naphthoquinones / Q000737:chemistry*; D011714:Pyrans / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
D016227:Benzoquinones; D009285:Naphthoquinones; D011714:Pyrans