Syntheses of Several Cyclopentano-Monoterpene Lactones Using 1,3-Dioxin Vinylogous Ester

Abstract

Formal syntheses of (±)-boschnialactone (5) and three cyclopentano-monoterpene lactones [i.e., (+)-iridomyrmecin (6), (±)-isoiridomyrmecin (7), and (±)-allodolicholactone (8)] have been accomplished in the form of the syntheses of 2-(methoxymethyl)-3-methyl-2-cyclopenten-l-one (11) and (±)-(4aα,7α,7aα)-hexahydro-7-methylcyclopenta[c]pyran-3(lH)-one (19), respectively, starting from 6,7-dihydrocyclopenta-l,3-dioxin-5(4H)-one (2). A synthesis of (±)~isodehydroiridomyrmecin (9) has also been achieved through a route including direct substitution of the hydroxy group of 2-(tert-butyldimethylsiIyloxymethyl)-3-methyl-2-cyclopenten-l-ol (22) with l-(tert-butyldimethylsilyloxy)-l-methoxyethene (23) as a key step. © 1995, The Pharmaceutical Society of Japan. All rights reserved.