A synthesis of fused acenaphthopyrrolizines via the 1,3-dipolar cycloaddition reaction of azomethine ylides with acetylenic esters.

An efficient synthesis of tetraalkyl 6a-hydroxy-3-alkyl-3H,6aH-acenaphtho[1,2-g] pyrrolizine-1,2,5,6-tetracarboxylates via the 1,3-dipolar cycloaddition reaction of azomethine ylides (generated in situ from [Formula: see text]-amino acids and acenaphthylene-1,2-dione) with dialkyl acetylenedicarboxylates is described. When glycine was used instead of alanine, phenylalanine, valine, or isoleucine, dialkyl (E)-1[Formula: see text]-(1,4-dialkoxy-1,4-dioxobut-2-en-2-yl)-2-oxo-[Formula: see text],5[Formula: see text]-dihydro-2H-spiro [acenaphthylene-1,2[Formula: see text]-pyrrole]-3[Formula: see text],4[Formula: see text]-dicarboxylates were obtained. The steric effects of the [Formula: see text]-amino acids side chains may be responsible for their different behaviors.