Silver oxide quinone synthesis

Synthesis by oxidation remains the first choice for commercial and laboratory preparation of quinones the starting material (1) provided the generic name quinone. This simple, descriptive nomenclature has been abandoned by Chemicaly hstracts, but remains widely used (2). The systematic name for (2) is 2,5-cyclohexadiene-l,4-dione. Several examples of quinone synonyms are given in Table 1. Common names are used in this article. 1,2-Benzoquinone (3,5-cydohexadiene-l,2-dione) (3) is also prepared by oxidation, often with freshly prepared silver oxide (3). Compounds related to (3) must be prepared using mild conditions because of their great sensitivity to both electrophiles and nucleophiles (4,5). 

There are numerous other examples of the synthesis of quinones employing reagents such as nitric acid, manganese dioxide, salcomine/02, silver oxide, " chromium oxidants, >2 -47... 

In 2012, Liao et al. disclosed total synthesis of ( )-schefflone 97 and tocopherol trimers 100 and 101 by the hetero-Diels-Alder trimerization of o-quinone methides 96 and 99, generated from the silver oxide-mediated oxidation of espintanol 95 and tocopherol 98, respectively (Scheme 28.33) [46]. 

A key step in a synthesis of the 6-deoxyanthracyclinone 4 involves, oxidation of 1 with silver(II) oxide to give the crude quinone a, which rearranges in the presence of a trace of IIC1 to the quinone 3 in high yield.1... 

Stille et al. completed the total synthesis of amphimedine (297) in eight steps and overall 21-23% yield (Scheme 33) (136). Their synthesis started with the readily available 4-quinolinone 298 (144), which was reacted with trifluoromethanesulfonic anhydride to give the triflate 299. Coupling of 299 with the organostannane 302 in the presence of Pd(PPhs)4 yielded the 4-arylquinoline 303, oxidation of which with ceric ammonium nitrate (CAN) or silver(II) oxide failed to produce any of the expected quinone. Thus,... 

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