TOTAL SYNTHESIS OF JATROPHATRIONE, AN UNPRECEDENTED TRICYCLIC ANTILEUKEMIC DITERPENE

TOTAL SYNTHESIS OF JATROPHATRIONE, AN UNPRECEDENTED [5.9.5] TRICYCLIC ANTILEUKEMIC DITERPENE 

Evans Chemical Laboratories The Ohio State University Columbus, Ohio 43210 

When subjected to the action of propanethiol under basic conditions (pH 9.2), jatrophone (2) undergoes a Michael reaction across its C8-C9 double bond, followed by facile transannular cyclization to give the tetracyclic diketone 3.2,9 The susceptibility of this enone part structure to conjugate addition has been proposed to constitute the event responsible for the pronounced biological activity of 2.9 

Among the other noteworthy structural features of 1 are its central nine-membered B ring that is home to three of the four stereogenic centers. The 1,5 relationship of two carbonyls such as those positioned at C7 and C14 has traditionally fostered transannular cyclizations in medium-sized rings. Accordingly, this 

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