Pyridinum chlorochromate

Following the procedure for the transformation of acetate (12) to (16), the acetate (13) was converted to trans-acetate (18). Reduction of (18) with metal hydride followed by oxidation of the resulting alcohol with pyridinum chlorochromate produced ketone (11), which afforded alcohol (17) by reduction with lithium aluminium hydride. 

A recent paper reports the oxidation of benzylic a-hydroxyphosphonates to aroylphos-phonates in good yields, by refluxing them with 10 equiv. of Mn02 in toluene The same paper reports that other oxidizing agents, including pyridinum chlorochromate and dichlorodicyanobenzoquinone (DDQ),or the Swem method are also applicable for the oxidation of benzylic a-hydroxyphosphonates to benzoylphosphonates. This approach to acylphosphonates was found, however, to be limited to tert-huty esters. ... 

MW irradiation also permitted a shorter reaction time for the selective solvent-free oxidation of primary, secondary, aUylic, and benzyhc alcohols with pyridinum sulfonate chlorochromate and pyridinum sulfonate fluoro-chromate as oxidizing agents, compared with the use of solvent. For example, cholest-5-en-3-ol acetate and cholest-5-en-3-ol benzoate were chemoselectively oxidized at position 7 in solvent-free conditions with 82% and 87% conversion, respectively. 

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