REARRANGEMENT OF ISOXAZOLINE-5-SPIRO DERIVATIVES .10. REGIOSELECTIVE NITRONE CYCLOADDITIONS TO METHOXYCARBONYLMETHYLENECYCLOPROPANE - SYNTHESIS OF PRECURSORS OF (PLUS-OR-MINUS)-LUPININE, (PLUS-OR-MINUS)-EPILUPININE AND (PLUS-OR-MINUS)-ELAEOKANINE-A
Fm. Cordero et al., REARRANGEMENT OF ISOXAZOLINE-5-SPIRO DERIVATIVES .10. REGIOSELECTIVE NITRONE CYCLOADDITIONS TO METHOXYCARBONYLMETHYLENECYCLOPROPANE - SYNTHESIS OF PRECURSORS OF (PLUS-OR-MINUS)-LUPININE, (PLUS-OR-MINUS)-EPILUPININE AND (PLUS-OR-MINUS)-ELAEOKANINE-A, Tetrahedron, 49(43), 1993, pp. 9867-9876
The cycloaddition of cyclic nitrones to methoxycarbonylmethylenecyclop
ropane (1) gives adducts having the methoxycarbonyl group on C4 of the
isoxazolidine ring with high regioselectivity. The thermal rearrangem
ent of the adducts gives quinolizidinone 6 and indolizidinones 8 beari
ng the methoxycarbonyl group selectively at C-1 and at C-8, respective
ly. The two compounds are intermediates for new formal syntheses of th
e alkaloids (+/-)-Lupinine and (+/-)-Epilupinine, and (+/-)-Elaeokanin
e A, respectively.