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DOI: 10.1055/sos-SD-021-00600

Smith, M. B.Science of Synthesis, (200521704.

The direct oxidation of nitrogen heteroaromatic compounds is a potentially attractive route to unsaturated lactams. In practice, this approach is limited, but useful for specific compounds. The oxidation of pyrrole is well known, and a limited number of oxidants are available.[‌243‌,‌244‌] Pyrrole and alkylpyrroles also undergo autoxidation, but this reaction has not been well studied.[‌245‌,‌246‌] Although oxidation is not a general route to lactams, simple unsaturated pyrrolidin-2-ones can be quickly accessed. For example, the direct oxidation of a dilute solution of pyrrole with aqueous hydrogen peroxide, gives 1,5-dihydropyrrolidin-2-one (180) and 1,3-dihydropyrrolidin-2-one (181) in a ratio of 9:1 in about 30% yield (Scheme 84).[‌247‌]

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