The regioselective synthesis of monomethoxynaphthylene diacetates
作者:Bhim C. Maiti、Oliver C. Musgrave、Douglas Skoyles
DOI:10.1016/j.tet.2004.12.034
日期:2005.2
Methods for the conversion of 1,4,5-naphthalenetriols into the corresponding monomethoxy diacetates are described. All utilise the formation of peri-bridged intermediates.
A synthesis of the pyranonaphthoquinone antibiotic (±)-frenolicin B[(±)-1] is described. Key step is the intramolecular palladium-catalyzed aryloxycarbonylation of the 2-allyl-1-naphthol derivatives 8a,b to give the tricyclic λ-lactones 6a,b. Only the former (6a) is converted successfully into (±)-deoxyfrenolicin, the immediate precursor of (±)-1.
Introduction of a 3-alkoxycarbonyl-2-propenyl group at the ortho position of phenol and naphthol via .ALPHA.-aryloxy-.GAMMA.-butyrolactone. Application to syntheses of (.+-.)-nanaomycin A and a 1-anthracenone.
Introduction of a (γ-alkoxycarbonyl) allyl group at the 2 position of 1-naphthol was achieved by a sequence of reactions involving a Claisen rearrangement, as illustrated in Chart 1, in overall yields of 62% (via 2a) and 50% (via 2b). By using the same technique, 5-methoxy- and 4, 5-isopropylidenedioxy-1-naphthols and 4-methoxyphenol were converted to the corresponding 4-aryl-2-butenoates (6a, b and 10), which underwent base-catalyzed cyclization to give dihydrofurans (7a, b and 11). Compounds 7a, b were readily transformed into (±)-nanaomycin A (14). 8, 10-Dimethoxy-1-anthracenone (19) was prepared from 6a in 77% yield by a standard method.
Untersuchungen an 1,4-Naphthochinonen, 11. Mitt. Farbstoffsensibilisierte Photooxidation von 1-Naphtholen mit Alkyl- und Alkoholfunktionen in 2-Position
作者:Gotthard Wurm、Uwe Geres
DOI:10.1002/ardp.19863190202
日期:——
Die Ergebnisse der farbstoffsensibilisierten Photooxidation von 2‐Alkylnaphth‐1‐olen sind abhängig von der Kettenlänge und dem Verzweigungsgrad der Alkylgruppe. Bei der Reaktion von 1a wird 3 als unerwartetes Produkt neben 2 identifiziert. Während der prim. Alkohol 5a zum entsprechenden Naphthochinon 8 oxidiert wird, entsteht aus dem sek. Alkohol 5b nicht 6, sondern das Keton 7, für das zwei unabhängige