Convenient route to both enantiomerically pure forms of trans-4,5-dihydroxy-2-cyclopenten-1-one: Efficient synthesis of the neocarzinostatin chromophore core

An enantioselective synthesis of an epoxybicyclo[7.3.0]dodecenediyne core s ystem of the neocarzinostatin chromophore has been achieved via intramolecu lar acetylide addition and palladium-mediated coupling of iodocyclopentene 5 with alkyne 6. The key cyclopentene moiety, trans-4,5-dihydroxy-2-cyclope nten-1-one 7, was conveniently prepared in both enantiomerically pure forms via enzymatic desymmetrization of meso-3,4,5-trans,trans-trihydroxycyclope ntene derivatives.