Total synthesis and assignment of the double-bond position and absolute configuration of (-)-pyrinodemin A.

[structure: see text] The first asymmetric total synthesis of a structurally novel cis-cyclopent[c]isoxazolidine alkaloid, (-)-pyrinodemin A (3), which exhibits potent cytotoxicity, has been accomplished through a highly diastereoselective intramolecular nitrone-olefin cycloaddition reaction as the key step. Thus, it has been found that the hitherto unknown absolute configuration of pyrinodemin A is as indicated in the structural formula 3.