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Please login to access the full content or check if you have access via Variation 5: γ-Lactams by Intramolecular Cyclization of Monoalkylketenes with Nitrogen Nucleophiles

DOI: 10.1055/sos-SD-023-00535

Tidwell, T. T.Science of Synthesis, (200623597.

Photochemical Wolff rearrangement of the diazo ketone 160 (R1=CO2Me; R2=H) gives the proline precursor 162 via an intermediate ketene 161 in good yield (Scheme 50).[‌110‌] Cyclization of diazo ketones 160 (R2=Ts) occurs through a silver benzoate induced thermal Wolff rearrangement in tetrahydrofuran to form the corresponding pyrrolidinones 162 (Scheme 50).[‌111‌] When this rearrangement is conducted in methanol, the pyrrolidinone is the sole product from 160 (R1=Me, Bn), whereas the methyl ester, formed through capture of the ketene, is the major or exclusive product from 160 (R1=H, CH2CH2SMe).[‌111‌]

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