Naoshi Nagai

Synthesis of 9a-deoxymitomycin congeners

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).

Lewis acid mediated claisen-type rearrangement of aryl dienyl ethers

Abstract In the presence of BF 3 ·.OEt 2 , aryl dienyl ethers were rearranged under mild conditions to afford dienyl phenols in good yields.

Stereoselectivity of photocycloaddition of azidoquinones to conjugated dienes

Photochemical reaction of 2-azido-1,4-quinones (1)–(3) with conjugated dienes (4)–(6) gives the corresponding 2-alkenyl-2,3-dihydroindoloquinones (7)–(14) with complete preservation of the original stereochemistry in their alkenyl moiety.