Synthesis and structure–activity relationship of violaceoid D, a cytotoxic alkylated phenol isolated from Aspergillus violaceofuscus Gasperini

The enantioselective synthesis of violaceoid D, a cytotoxic phenolic compound isolated from the culture broth of Aspergillus violaceofuscus Gasperini, was achieved. The total synthesis involves stereoselective construction of the stereogenic center of violaceoid D via Sharpless asymmetric dihydroxylation, followed by Smiles rearrangement. The absolute configuration of natural violaceoid D was determined to be R from the specific rotation value. Synthesized violaceoid D and its analogs were evaluated for cytotoxicity against two human cancer cell lines, Jurkat and HCT116. Because the enantiomer of violaceoid D showed no cytotoxicity, it is plausible that violaceoid D binds selectively to specific target molecules, such as proteins in the cancer cells.