title: Studies Directed toward the Synthesis of the Unusual Antileukemic Diterpene Jatrophatrione. 2. Functionalization of Advanced Polycyclic Precursors to the 9-Epi and 8,9-Dehydro Congeners.
abstract: The synthesis of highly functionalized [5.9.5]tricyclic systems closely related to jatrophatrione (1) and 9-epijatrophatrione (2) is described. The first set of experiments provides a route to the conjugated 7-methylene ketones 8 and 9, both of which resist migration of the exocyclic double bond to a position internal to the ring. Subsequent dihydroxylation studies define a convenient pathway from 3 to triketone 20, which has yet to exhibit a tendency to undergo appropriate dehydration at the tertiary carbinol center. The presence of a carbonyl group in ring C was shown not to be contributory to this low reactivity. Finally, a protocol involving formation of a bromo oxetane with subsequent introduction of a C8-C9 double bond and Grob fragmentation has shown promise for arrival at 1 and/or 2 by making available the diene 36.
authors.affiliation: Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, and Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487.
authors.forename: Leo A.
authors.initials: LA
authors.lastname: Paquette
authors.forename: Scott D.
authors.initials: SD
authors.lastname: Edmondson
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Monck
authors.forename: Robin D.
authors.initials: RD
authors.lastname: Rogers