Galbulimima

Lew Mander of the Australian National University recently reported (J. Am. Chem. Soc. 2003. /25, 2400) the total synthesis of the pentacyclic alkaloid GB I3 3, which had been isolated from the bark of the rain forest tree Galbulimima belgraveana. In the course of the synthesis, he took full advantage of benzene precursors, while at the same time carefully establishing each of the eight stereogenic centers of... 

This family is found from eastern Malaysia to northern Australia. It i alkaloidal, nine out of nine samples of Galbulimima balgravea-na Were found to be positive. 

Himantandra (Galbulimima) baccata, H. belgraveana (Himantandraceae) [bark]... 

The total synthesis of galbulimima alkaloid GB 13 was accomplished by L.N. Mander and co-workers. The Birch reduction of a complex intermediate was necessary in order to prepare a cyclic a,p-unsaturated ketone. The treatment of the substrate with lithium metal in liquid ammonia first resulted in a quantitative reductive decyanation of the C6a cyano group. The addition of excess ethanol to the reaction mixture reduced the aromatic ring to the corresponding enol ether that was hydrolyzed in a subsequent step to afford the unsaturated ketone. 

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