Tin tetrachloride → (1R,10R,11S,16S)-4,6-dimethoxy-1,11,15,15-tetramethyl-8-oxatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene

Participants

Reaction Conditions

Reaction Steps

To a solution of (1S,2R,4aS,8aS)-1-(2,4-dimethoxyphenoxymethyl)-2,5,5,8a-tetramethyl-decahydronaphthalen-2-ol (41) (0.90 g, 2.4 mmol) in CH2Cl2 (20 mL), cooled to −78° C., a solution of SnCl4 (1.11 mL, 9.56 mmol) in CH2Cl2 (10 mL) was added dropwise. The temperature was maintained at −78° C. for 4 h then the mixture was allowed to warm to room temperature overnight. The reaction was quenched with water (50 mL). The organic layer was separated, dried (Na2SO4) and concentrated. Purification by column chromatography on silica gel (Hexanes/EtOAc, 4:1) gave (1R,10R,11S,16S)-4,6-dimethoxy-1,11,15,15-tetramethyl-8-oxatetracyclo[8.8.0.02,7.011,16]octadeca-2,4,6-triene (Compound No. 42) (0.69 g, 80%) as a viscous yellow oil. 1H NMR (CDCl3): δ 6.33 (d, 1H), 6.00 (d, 1H), 4.45 (m, 1H), 4.18 (t, 1H), 3.83 (s, 3H), 3.75 (s, 3H), 2.25 (m, 1H) 1.80-1.38 (m, 7H), 1.35 (s, 3H), 1.25-1.00 (m, 4H) 0.92 (s, 3H), 0.87 (s, 3H), 0.82 (s, 3H).

Provenance & Evidence