Functionalized hexahydroanthracene

When zinc and a,a -dibromo-o-xylene are irradiated with ultrasonic waves at room temperature, synthetically useful quantities of the reactive intermediate, o xylylene, are generated which can be treated in situ with activated olefins to give good yields of cycloaddition products(30). Chew and Ferrier used this methodolgy to generate a-xylylene for the synthesis of optically pure functionalized hexahydroanthracenes(31). The reaction with lithium takes a different course(19). Rather than generate the -xylylene intermediate, ionic species are produced. The two fates of a, a -dibromo-o-xylene are presented in the scheme below ... 

The IBX oxidation of diol 836 has been utilized in the synthesis of the functionalized hexahydroanthracene dione 837 (Scheme 3.331), a model for the D ring of taxoids [1136]. 

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