Synthesis of 9a-deoxymitomycin congeners

Abstract

The protected mitosane (23) is prepared in stereospecific manner. The key reactions included in the synthetic scheme are (i) Lewis acid-mediated Claisen-type rearrangement of the penta-2,4-dienyl aryl ether (10) to the penta-2,4-dienylphenol (11), (ii) the regioselective incorporation of the alkoxymethyl group at the 1-position of the pentadienyl side-chain in the protected pentadienylhydroquinone (12), and (iii) the stereospecific copper-catalysed double cyclization of the azido(penta-2,4-dienyl)quinone (15) to the 3H-pyrrolo[1,2-a]indole-5,8-dione (16) in one step. Subsequent stereospecific introduction of the aziridine ring furnishes the target compound (23).