The stereoselective formation of naphtho[1,2-c]pyrans, angular analogues of the aphin-derived glucoside B, by an intramolecular version of the Mukaiyama reaction of 4-naphthyldioxolanes

Giles, R.G.F., Green, I.R., Knight, L.S., Lee Son, V.R. and Yorkea, S.C. (1994) The stereoselective formation of naphtho[1,2-c]pyrans, angular analogues of the aphin-derived glucoside B, by an intramolecular version of the Mukaiyama reaction of 4-naphthyldioxolanes. Journal of the Chemical Society, Perkin Transactions 1 (7). pp. 865-873.

Abstract

Stereoselective isomerisation of the pair of epimers rel-(2R,4S,5S)- and rel-(2S,4S,5S)-4-(4-isopropoxy-5,7-dimethoxynaphthalene-2-yl)-2,5-dimethyl dioxolane 12 with an excess of a mixture of titanium tetrachloride and titanium tetraisopropoxide afforded the two products rel-(1R,3S,4S)-3,4-dihydro-4-hydroxy-6-isopropoxy-7,9-dimethoxy-1,3-dimethylnaphtho[1,2-c]pyran 13, and the C-1 epimer 15. Isomerisation of rel-(2S,4R,5S)-4-(8-bromo-4-isopropoxy-5,7-dimethoxynaphthalen-2-yl)-2,5-dimethyl dioxolane 36 with an excess of titanium tetrachloride alone afforded rel-(1S,3S,4R)3,4-dihydro-4-hydroxy-6-isopropoxy-7,9-dimethoxy-1,3-dimethylnaphtho[1,2-c]pyran 38 and its 5-bromo derivative 39, the latter being formed through bromine migration on the aromatic nucleus.

Item Type:	Journal Article
Publisher:	Royal Society of Chemistry
Copyright:	© 1994 Royal Society of Chemistry
URI:	http://researchrepository.murdoch.edu.au/id/eprint/35913

Item Control Page