Concise and stereoselective synthesis of the N7-C25 fragment of psymberin

The N-7-C-25 fragment of the potent and selective cytotoxic agent psymberin has been prepared through a short (12 linear steps, 15 total steps) and stereoselective sequence. Highlights of this route include a very rapid construction of the pentasubstituted arene, a substrate-controlled diastereoselective fragment coupling using a Mukaiyama aldol reaction, and an efficient entry into a key tetrahydropyranyl cyanide.