Conduritols catalytic oxidation

On catalytic oxidation, conduritol C (66) gives (in just 10 min.) the ketone (66a), the quasi-equatorial hydroxyl group at C-1 (but neither the axial hydroxyl group at C-2 nor the quasi-equatorial hydroxyl group at C-4) being oxidized. The same ketone (66a) can also be prepared by oxidation of natural conduritol A (67). Both possible half-chair conformations of conduritol A (67) are equally stable, and hence there presumably exists an equilibrium in which the group at C-1, as well as that at C-4, is attacked and a racemate (66a) is produced. 

Conduritol E (68), having two quasi-axial hydroxyl groups gives, on catalytic oxidation, only the monoketone (69). Oxidation of both quasi-axial hydroxyl groups to the diketone does not, therefore, normally occur. Conduritol D (69a) gives, on catal3d ic oxidation, the readily crystallizable ketone (69b). 

Catalytic oxidation of all six conduritols has been studied. In each case, an allylic hydroxyl group was oxidized, regardless of the configuration or conformation, giving a trihydroxycyclohexenone (122). ... 

The quasi-hydroxyl groups in the cyclohexenetetrols are even more readily oxidized catalytically. All six posable stereoisomers of the conduritols were carefully investigated with respect to their relative ease of catal3Ttic oxidation. Conduritol B (63b) has two equatorial hydroxyl groups on C-2 and C-3, and two quasi-equatorial hydroxyl groups on C-1 and C-4. Under these circumstances, conduritol B would not be expected to... 

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