Diacyl Disulfide: A Reagent for Chemoselective Acylation of Phenols Enabled by 4‑(<i>N</i>,<i>N</i>‑Dimethylamino)pyridine Catalysis

A general and excellent acylation reagent, diacyl disulfide, was uncovered for efficient ester formation enabled by DMAP (4-(<i>N</i>,<i>N</i>-dimethylamino)­pyridine) catalysis. This protocol offered a promising synthetic platform on site-selective acylation of phenolic and primary aliphatic hydroxyl groups, which greatly expanded the realm of protecting group chemistry. The importance of the reagent was also reflected by its excellent moisture tolerance, high efficiency, and potential in synthetic chemistry and biologically meaningful natural product modification

Yangonindimers A-C, three new kavalactone dimers from <i>Piper methysticum</i> (kava)

<p>Three new kavalactone dimers, designated as yangonindimers A-C (<b>1</b>–<b>3</b>), along with one known analogue were isolated from the roots of <i>Piper methysticum</i>. Their structures were elucidated via extensive analysis of their 1D, 2D NMR and mass spectroscopic data. All these dimers possess a skeleton featuring a cyclobutane ring connecting two kavalactone units. Compounds <b>1</b>–<b>4</b> were evaluated for their cytotoxic activities against human tumour cell lines NCI-H46, SW480 and HepG2, but none showed significant activity.</p