Enantioselective synthesis for the (-)-antipode of the pyrazinone marine alkaloid, hamacanthin A

A short enantioselective total synthesis for the (-)-antipode of the antifu ngal marine alkaloid, hamacanthin A, (6R)-3,6-bis(6-bromoindol-3-yl)-5,6-di hydro-2(1H)-pyrazinone, is described. This synthesis proceeds through the c oupling of 3-indolyl-alpha -oxoacetyl chloride and 3-indolyl azidoethylamin e, followed by intramolecular aza-Wittig type cyclization, A concise and us eful approach for the synthesis of (1R)-1-(indol-3-yl)-2-azidoethylamine us ing the Sharpless asymmetric dihydroxylation reaction followed by stereospe cific azidation is also presented.