“…Preparation of the 3a-Methyloctahydro-(2 and 3) and -3,3a,5a,6,9,9a-hexahydro-5H-pyrrolo[1,2-a][3,1]benzoxazin-1(2H)-ones (4 and 5) and Di-endo (6 and 8) and Di-exo (7 and 9) 6,9-Methano Analogues: 4-Oxopentanoic acid (1, 1.2 g, 0.010 mol, Acros 12.514.01 levulinic acid, 98ϩ%), a cyclic or bicyclic amino alcohol [1.3 g of cis-or trans-2-(hydroxymethyl)cyclohexyl-1-amine, [39] or 1.3 g of cis-or trans-2-(hydroxymethyl)-4-cyclohexenyl-1-amine, [40] or 1.4 g of di-exo-or di-endo-3-aminobicyclo[2.2.1]hept-2-ylmethanol or 1.4 g of -hept-5-en-2-ylmethanol; [41,42] 0.010 mol], and PTSA (0.05 g) in toluene (50 mL) was heated under reflux for 2 h. After evaporation of the solvent, the residue was transferred to a chromatography column (alumina, Acros, activated, basic, 50Ϫ200 µ) and eluted with EtOAc. The physical data for compounds 2Ϫ9 are listed in Table 4.…”