SIMPLE TOTAL SYNTHESES OF BIOLOGICALLY-ACTIVE PENTATHIADECANE NATURAL-PRODUCTS, 2,4,5,7,9-PENTATHIADECANE 2,2,9,9-TETRAOXIDE (DYSOXYSULFONE), FROM DYSOXYLUM-RICHII, AND 2,3,5,7,9-PENTATHIADECANE 9,9-DIOXIDE, THE MISIDENTIFIED LENTHIONINE PRECURSOR SE-3 FROM SHIITAKE MUSHROOM (LENTINUS-EDODES)

Brief total syntheses are reported for 2,4,5,7,9-pentathiadecane 2,2,9,9-tetraoxide (dysoxysulfone, 1), from the Fijian tree Dysoxylum richii, 2,3,5,7,9-pentathiadecane 9,9-dioxide (8), from shiitake mushroom (Lentinus edodes),and 2,4,5,7-tetrathiaoctane 2,2-dioxide (2a) from Tulbaghia violacea, starting from 1,2,4-trithiolane (4) for 1, 1,2,4,6-tetrathiepane (5) for 8, and 2,4,5,7-tetrathiaoctane (9) for 2a and employing regiospecific oxidation of intermediate penta- or tetrasulfides using KMnO4 along with Zn(OAc)(2) or FeCl3 to prevent product degradation by the base produced during oxidation.