SYNTHESIS OF HELICALLY CHIRAL MOLECULES - STEREOSELECTIVE TOTAL SYNTHESIS OF THE PERYLENEQUINONES PHLEICHROME AND CALPHOSTIN-A

The total syntheses of the perylenequinone natural products phleichrom e and calphostin A are detailed. The syntheses were based on (1) the d e novo construction of regiospecifically oxygenated and selectively pr otected naphthalene subunits, (2) the enantiospecific introduction of the stereogenic side chains using a chiral (alpha-alkoxyalkyl)-lithium reagent, and (3) a highly atropdiastereoselective Cu(I)-promoted biar yl synthesis for the stereoselective introduction of the helical axis of the calphostins. The total syntheses were achieved in 13 or 14 step s, respectively, with excellent control of absolute stereochemistry.