Gilvocarcins

Biosynthetically, the polyketide-derived backbone of gilvocarcins is formed from two distinct starter units (acetate, and proprionate), which condense nine malonate subunits by the action of a type II PKS. 

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In 1992, Suzuki and coworkers disclosed the total synthesis of (+)-gilvocarcin M, the enantiomer of naturally occurring (-)-gilvo-... 

Scheme 5. Acid-induced anomerization of the gilvocarcin-type glycosidic linkage.

Due, in large part, to the promising antitumor activity of gilvocarcin V (2), it was of interest to modify the approach outlined above so that a total synthesis of 2 could also be achieved. Not surprisingly, the gilvocarcin V synthesis exercised the same basic strategy that was so successful in the synthesis of gilvocarcin M... 

The completion of the synthesis of gilvocarcin V (2) only requires a few functional group manipulations. Hydrogenolysis of the four benzyl groups, followed by acetylation of the liberated hydroxyl groups, provides 30 in 68 % overall yield. After cleavage of the MOM ether in 30 with bromotrimethylsilane, application... 

The synthesis of the naphthalene rings found in the gilvocarcin group and in the rubromycin class of natural products via benzannulation was also reported. Both classes show promising antitumour activity [67,68]. 

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