Rearrangement of Isoxazoline-5-spiro Derivatives. Part 10. Regioselective Nitrone Cycloadditions to Methoxycarbonylmethylenecyclopropane: Synthesis of Precursors of (+/-)-Lupinine, (+/-)-Epilupinine and (+/-)-Elaeokanine A

Article abstract of DOI:10.1016/S0040-4020(01)80188-5

The cycloaddition of cyclic nitrones to methoxycarbonylmethylenecyclopropane (1) gives adducts having the methoxycarbonyl group on C-4 of the isoxazolidine ring with high regioselectivity.The thermal rearrangement of the adducts gives quinolizidinone 6 and indolizidinones 8 bearing the methoxycarbonyl group selectively at C-1 and at C-8, respectively.The two compounds are intermediates for new formal syntheses of the alkaloids (+/-)-Lupinine and (+/-)-Epilupinine, and (+/-)-Elaeokanine A, respectively.