[GRAPHICS]The synthesis of pyranonaphthoquinone-spiroacetals (3 and 4), which are synthetic analogues of the pyranonaphthoquinone antibiotic griseusin A (1) is reported. The oxygenated substituents on the spiroacetal ring were introduced onto the key naphthalene intermediate (5) using an anti asymmetric aldol reaction. The pyranonaphthoquinone skeleton was then assembled via furofuran annulation to naphthoquinone (22) to construct a furonaphthofuran ring followed by oxidative rearrangement to the furonaphthopyran ring.
A titanium naphtholate approach for the synthesis of analogues of griseusin A †
作者:Margaret A. Brimble、Michael R. Nairn、Josephine S. O. Park
DOI:10.1039/a909243i
日期:——
oxazolidinone 5 with aldehyde 6 using tin(II) triflate and tetramethylethylenediamine afforded adduct 8 with the required 2′,3′-anti 3′,5′-syn stereochemistry as the major product. Aldol adduct 8 was then converted into aldehyde 12. The titanium naphtholate generated from naphthol 21 using TiCl3OiPr then afforded alcohol 26 upon addition of aldehyde 12. Oxidation of alcohol 26 afforded ketone 29 which underwent
作者:Margaret A Brimble、Michael R. Nairn、Josephine Park
DOI:10.1021/ol991020c
日期:1999.11.1
[GRAPHICS]The synthesis of pyranonaphthoquinone-spiroacetals (3 and 4), which are synthetic analogues of the pyranonaphthoquinone antibiotic griseusin A (1) is reported. The oxygenated substituents on the spiroacetal ring were introduced onto the key naphthalene intermediate (5) using an anti asymmetric aldol reaction. The pyranonaphthoquinone skeleton was then assembled via furofuran annulation to naphthoquinone (22) to construct a furonaphthofuran ring followed by oxidative rearrangement to the furonaphthopyran ring.