Question

Integrated Problem 16.70 During the first total synthesis of chelidonine, a cytotoxic natural product isolated from the root of Chelidonium majus, the investigators used only heat to achieve the following transformation (). Am. Chem. Soc. 1971, 93, 3836-3837). Propose a plausible mechanism for this thermal cyclization process. Include lone pairs and charges in your answer. Do not draw out any hydrogen explicitly in your products. Do not use abbreviations such as Me or Ph. sah 120°C

Answer 1

4+2 cycloaddition reaction gives cyclohexene ring