Formaldehyde → (3aR,6aR)-5-methyl-1-[(1R)-1-phenylethyl]-2,3,3a,4,6,6a-hexahydropyrrolo[3,2-c]pyrrole

Participants

Reaction Conditions

Reaction Steps

37% aqueous formaldehyde (1.6 L) was added to a solution of (3aR,6aR)-1-[(1R)-1-phenylethyl]-3,3a,4,5,6,6a-hexahydro-2H-pyrrolo[3,2-c]pyrrole (Intermediate 39, 108 g, 0.5 mol) in HCOOH (800 mL) at r.t., then the mixture was stirred at 70-80° C. for 2 h. The mixture was then cooled to 0° C. and basified with solid NaOH to pH-13. This mixture was then extracted with CH2Cl2 (2×2 L). The combined organic solutions were concentrated in vacuo. Purification by FCC, eluting with 2:1 to 1:10 hexanes/EtOAc, gave the title compound (80 g, 70%) as red oil; 1H NMR: (CDCl3) 1.36 (3H, d), 1.65 (1H, m), 1.85 (1H, m), 2.22 (3H, m), 2.32 (3H, s), 2.54 (1H, m), 2.68 (2H, m), 2.83 (1H, m), 3.10 (1H, m), 3.40 (1H, m), 7.21-7.33 (5H, m).

Provenance & Evidence