Tandem Achmatowicz-Knoevenagel protocol: diastereoselective synthesis and anticancer evaluation of cyclopenta[b]pyrane derivatives.

Synthesis of cyclopenta[b]pyrane derivatives via Achmatowicz oxidative cyclization of furanols followed by intramolecular Knoevenagel condensation of the β-ketoester arm is examined. The extent of diastereoselectivity was dependent on the nature of the chiral atom within the tethering carbon of the pyrenone ring. In some cases, this process proceeds with a high degree of stereoselectivity after protection of the anomeric hydroxyl group. Furthermore, the cytotoxic activity of pyrazolone derivatives thereof was studied against HCT116 (human colorectal cancer cells), SK-N-SH (human Caucasian bone marrow neuroblastoma) cells and the non-tumorigenic cells (MCF10A).