Naphthoquinones chalcone

Whereas the chalcones represent model substrates for the evaluation of new oxidations protocols, many authors have applied these exact or similar conditions to the epoxidation of naphthoquinones and quinone derivatives. Thus, Taylor s group epoxidized quinone-acetal 97 (Scheme 12.23) in good ee (89%) and moderate yield (32%). Epoxide 98 was used in the synthesis of (+)-Manumycin A [154]. Other naphthoquinones have been oxidized in good yields using similar conditions and slight modifications on the cinchona catalyst [155]. 

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