Total Synthesis and Anticancer Activity of (+)-Hypercalin C and Congeners

Abstract

The hypercalins are dearomatized acylphloroglucinols with a pendant complex cyclopentane ring that exhibit activity against several cancer cell lines. We report the first total synthesis of (+)-hypercalin C employing a convergent strategy that enabled the dissection of the essential structural features required for the observed anticancer activity. A strategic disconnection involving an unusual C ${\mathrm{sp}{3}^{}}_{}$ -C ${\mathrm{sp}{2}^{}}_{}$ Suzuki-Miyaura coupling with an α-bromo enolether also revealed an unexpected C-H activation. This strategy targeted designed analogues along the synthetic route to address particular biological questions. These results support the hypothesis that hypercalin C may act as a proton shuttle with the dearomatized acylphloroglucinol moiety being essential for this activity.

Keywords: C−H insertion; Suzuki-Miyaura coupling; chiral pool; protonophore; β-lactone.