A FULLY SYNTHETIC ROUTE TO THE PAPULACANDINS. STEREOSPECIFIC SPIROACETALIZATION OF A C-1-ARYLATED METHYLGLYCOSIDE

Article abstract of DOI:10.1016/S0008-6215(00)90895-4

Lewis acid-catalyzed, hetero Diels-Alder reaction of (E)-1-methoxy-3-trimethylsilyloxy-1,3-butadiene, with 6-benzoyloxymethyl-2,4-dibenzyloxy benzaldehyde afforded 2-(6-benzoyloxymethyl-2,4-dibenzyloxyphenyl)-2,3-dihydro-4H-pyran-4-one.This was converted into a derivative of papulacandin D by a stereospecific, spiroacetalization of a C-1 methoxylated aryl glycoside, <3,5-dibenzoyloxy(methyl 3-O-acetyl-4,6-di-O-benzoyl-DL-glucopyranosid-1-yl)phenyl>methyl benzoate.