Total synthesis of quassinoids

J. Herscovici, S. Delatre, L. Boumaiza, and K. Antonakis, Stereocontrolled routes to functionalized [1,8-bcJ-naphthopyran—a study on the total synthesis of quassinoids and tetra-hydronaphthalene antibiotics, J. Org. Chem. 58 3928 (1993). 

Hirota, in the total synthesis of quassinoid amaroUde 257 [56], used a nonacidic catalysis with pentachlorophenol. Under these conditions and in the presence of 4 A molecular sieves, the expected ester 259 was obtained in moderate yield. However, large amounts of starting material were recovered. The diastereo-... 

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