Organic Chemistry

Total Synthesis of Ritterazine B

Michael Maser California Institute of Technology


The first total synthesis of the cytotoxic alkaloid ritterazine B is reported. The synthesis features a unified approach to both steroid subunits, employing a titanium-mediated propargylation reaction to achieve divergence from a common precursor. Other key steps include gold-catalyzed cycloisomerizations that install both spiroketals, and late stage C–H oxidation to incorporate the C7′ alcohol.

Version notes

V2: Update funding acknowledgments and revise TOC graphic coloring


Thumbnail image of 2021-02-04_ritterazine_B.pdf
download asset 2021-02-04_ritterazine_B.pdf 2 MB [opens in a new tab]

Supplementary material

Thumbnail image of 2021-01-26_ritterazine_B_SI.pdf
download asset 2021-01-26_ritterazine_B_SI.pdf 29 MB [opens in a new tab]
2021-01-26 ritterazine B SI