Total synthesis of (+)-asperazine

The first total synthesis of the structurally novel cyclotryptophan alkaloid asperazine is reported. The central step in the synthetic sequence is a diastereoselective intramolecular Heck reaction in which the substituent controlling stereoselection is external to the ring being formed. This synthesis confirmed the structure of (+)- asperazine (1) proposed by Crews and co- workers and provided material for additional biological studies. The in vitro cytotoxicity originally reported for the marine isolate was not confirmed with synthetic (+)- asperazine. (c) 2007 Elsevier Ltd. All rights reserved.