Making a Methyl Ester

Cyanohydrin-oxidation-substitution sequence (Corey method) [1]  

With the exception of the Corey method, all transformations are isohypsic. The Corey method involves hydrogen cyanide (HCN) as a sacrificial reagent to produce the intermediate cyanohydrin that is then oxidized to a cyanoketone and finally the cyano group is substituted by a methoxy group. The Fischer esterification and carbonylation methods do not involve sacrificial reagents. The former 

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