Ohauamines A–D, Structurally Unprecedented Tricyclic Depsi-tripeptides from the New Zealand Ascidian Pycnoclavella kottae

Four structurally unprecedented tricyclic depsi-tripeptides, ohauamines A-D (1-4), were isolated from the New Zealand endemic ascidian Pycnoclavella kottae. Planar structures were elucidated by extensive use of ¹H-, ¹³C-, and ¹⁵N-based NMR experiments, with absolute configurations established by computational methods.