Abstract This article describes chemoselective and atom-economic methods for the stereoselective assembly of the ring A and B subunits of bryostatins. A Ru-catalyzed tandem alkene–alkyne coupling/Michael addition reaction was developed and applied to the synthesis of bryostatin ring B. We explored an acetylide-mediated epoxide-opening/6-exo- dig cyclization route to access the bryostatin ring A, although ring A was eventually ...
