Efficient synthesis of the tetracyclic aminoquinone moiety of marmycin A.

Nathan Maugel, Barry B Snider

Department of Chemistry MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA.

Organic letters 2009 Nov 5

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An efficient four-step route to the tetracyclic aminoquinone moiety of marmycin A that proceeds in 41% overall yield from 5-nitronaphthoquinone and 5-methyl-1-vinylcyclohexene will facilitate preparation of marmycin A analogues for biological evaluation. The Diels-Alder reaction gave exclusively the desired adduct that is favored by steric considerations rather than the regioisomeric adduct that is favored by electronic considerations.