serine/threonine phosphatase (proteinphosphatase 1 and 2A) inhibitors constitute a biologically and structurally interesting class of natural products. Among this class of inhibitors are cyclicpentapeptides (nodularins) and cyclic heptapeptides (microcystins), both of which inhibit at the nanomolar level and are the only peptide inhibitors of these enzymes. Described herein is the total synthesis of motuporin