| The cephalostatins and ritterazines represent an intriguing class of marine natural products in both structure and biological activity, and the progress towards the synthesis of high valued analogs with a focus on process orientated methodology is described herein. Included in the pages to follow, is the further advancement of the 'Red-Ox' strategy toward the highly efficient synthesis of 25-epi-4,15-dihydro-North 1, Chapter 2. A short review focusing on the earlier efforts toward the main synthetic challenges of North 1 analogs and the lessons learned to propel the efficient stereoselective synthesis of anti-cancer spiroketals is presented. The development of a new 'Plug and Play' titanium(II) alkylidenation approach for the synthesis of &agr;-functionalized spiroketals is presented in Chapter 3. Highlighting the new strategy, is the process efficient synthesis of the a key enol ether intermediate as the gateway to the synthesis of 26,27-dihydroxy North 1 and other spiroketal analogs. The use of silyl triflates for tandem one pot kinetic resolution of diastereomers is also presented. |
