Bengamides B and E

Bengamide B	Bengamide E

The bengamides are marine natural products discovered in the coral reefs off the Fiji Islands. These products have shown antiproliferative characteristics against transformed and nontransformed cells. Most successfully the bengamides B, E and Z showed inhibition against cancer growth in MDA-MB-435 human breast cells implanted in athymic mice. Unfortunately, to run some of these tests more bengamides were needed, and isolation from sponges was a lengthy, low-yielding process. While there are presently total syntheses for bengamides A, B and E, they are very lengthy syntheses of 14-15 steps for Bengamide E and 30-32 steps for Begnamide B. The first total synthesis yields bengamide E. The second total synthesis utilizes the last lactone intermediate in the bengamide E total synthesis and combines it with its final intermediate to yield Bengamide B.