Collin s reagent

Selective oxidation of secondary alcohols to ketones is usually performed with CrOj/HjSO, I I in acetone (Jones reagent) or with CrOjPyj (Collin s reagent) in the presence of acid-sensitive groups (H.G. Bosche, 1975 C. Djerassi, 1956 W.S. Allen, 1954). As mentioned above, a,)S-unsaturated secondary alcohols are selectively oxidized by MnOj (D.G. Lee, 1969 D. Arndt, 1975) or by DDQ (D. Walker, 1967 H.H. Stechl, 1975). 

These olefins were transformed into unsaturated acetates by Woodward s protocol with iodine, silver acetate, and acetic acid. Saponification and subsequent oxidation of the liberated alcohols with Collin s reagent resulted in a 2 1 mixture of conjugated enones, 162 and 163, in mediocre yields (Scheme 16). The minor enone 163 was transformed into the cyanoketone 164 by 1,4-addition using... 

Alkylation of the acetylenic anion with isobutyraldehyde gave the propargylic alcohol which was then oxidized using Collin s reagent to yield the requisite ketone. 

Oxidative decomplexation of the above described palladium alkyl or allyl complexes with Collin s reagent gave norbornenones 20 and nortricyclenones 21 in varying ratios depending on the starting material. ... 

Oxidative Decomplexation of Nortricyclenones from Palladium Complexes with Collin s Reagent General Procedure ... 

Oxidative decomplexation of palladium complexes obtained via methanol addition to norbor-nadiene with Collin s reagent [chromium(Vl)oxide-pyridine)2] leads to norbornenones 32 and nortricyclenones 33. ... 

Eremophilane sesquiterpenes are not widely distributed in Eremophila species. In fact, the only other example so far known is the aldehyde (70) which occurs in E. rotundifolia (66). The structure of 70 was deduced largely from H- and C-nmr spectral data and, the absolute, stereochemistry by correlation with eremophilone. The keto aldehyde was reduced with sodium borohydride-cerium trichloride to give a mixture of diastereomeric diols. The major compound was assigned the 9a-configuration. The derived diacetate, on treatment with lithium-diethylamine, gave mainly the 9-allylic alcohol which was oxidised to eremophilone with Collin s reagent. 

Write out the product formed when allyl alcohol is oxidized with Collins s reagent and when benzyl alcohol is oxidized with Collins s reagent. 

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