Studies on the synthesis of the ABC rings of (+/-)-hexacyclinic acid.
A synthesis of the ABC-rings of the polyketide natural product hexacyclinic acid has been achieved. The B-ring was formed first via an intramolecular ester-tethered Diels-Alder reaction, and the A-ring was annulated to this by means of a SmI(2) mediated reductive 5-exo-trig cyclization of a samarium-ketyl radical onto a vinyl group. Finally, the C-ring was closed using olefin metathesis. Interestingly, use of enyne metathesis resulted in the synthesis of a more functionalized 5-membered C-ring in a model system, but an undesired 6-membered C-ring in the actual system. An investigation of this change in selectivity is discussed.
Clarke
Paul A
PA
Department of Chemistry, University of York, Heslington, York, North Yorks YO10 5DD, UK. pac507@york.ac.uk
Cridland
Andrew P
AP
Rolla
Gabriele A
GA
Iqbal
Mudassar
M
Bainbridge
Nigel P
NP
Whitwood
Adrian C
AC
Wilson
Claire
C
D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure
D006576:Heterocyclic Compounds, 4 or More Rings; C502347:hexacyclinic acid