Syntheses in enantiopure form of four diastereoisomeric naphthopyranquinones derived from aphid insect pigments
Aggarwal, R., Giles, R.G.F., Green, I.R., Oosthuizen, F.J. and Taylor, C.P. (2005) Syntheses in enantiopure form of four diastereoisomeric naphthopyranquinones derived from aphid insect pigments. Organic & Biomolecular Chemistry, 3 (2). p. 263.
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The first syntheses are described of the four enantiopure naphthopyranquinones (1R,3R,4S)- and (1R,3R,4R)-3,4-dihydro-4,7,9-trihydroxy-1, 3-dimethylnaphtho[2,3-c]pyranquinone (quinone A 1 and quinone A' 2) and their two C-3 epimers, the (1R,3S,4S)- and (1R,3S,4R)-diastereoisomers 5 and 6, using enantiopure lactate as the source of asymmetry. Key factors in these syntheses are the maintenance of stereochemical integrity throughout the sequences and intramolecular diastereoselective cyclisations of the titanium phenolates of phenolic lactaldehydes. For these cyclisations the differing degree of diastereoselectivity is explained as are the stereochemistries of the product 2-benzopyran-4,5-diols.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Chemical and Mathematical Science|
|Publisher:||Royal Society of Chemistry|
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