Answers are grounded in this paper and cite their sources.
Treatment of amides 1a,b with thionyl chloride followed by reaction with triethylamine gave 1,4‐dihydro[1]benzopyrano[4,3‐b]pyrrole derivatives (4a,b) arising from intramolecular 1,3‐cycloaddition of intermediate nitrile ylides (3a,b).
No takes yet. Share an insight, caveat, or question.
Garanti et al. (1977) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: