Anodic Methoxylation Using Recyclable Solid-Supported Bases

Significance

Silica gel-supported piperidine 1 was developed as a precursor of a supported electrolyte. Thus, anodic oxidation of sulfide 2 in methanol in the presence of the supported base 1 gave methoxylated product 3 in 76% yield, where the protonated 1·methoxide was generated in situ as a supported electrolyte. After the electrolysis, the silica gel-supported compound 1 was readily recovered by simple filtration and reused (10 times). The yield of methoxylated product 2 was always more than 70% and did not decrease at all upon reuse of the silica gel-supported piperidine. The appearance of silica gel-supported piperidine did not change at all before and after electrolysis.