Nitrogen → trans-3,4',5-Trimethoxy-4-(trifluoromethanesulfonyloxy)stilbene

Beteiligte Stoffe

Reaktionsschritte

To a round-bottomed flask (50 mL) equipped with magnetic stir bar and N2 bubbler was charged 6 (600 mg, 2 mmol), pyridine (332 mg, 4 mmol, 2 equiv) and CH2Cl2 (20 mL) The mixture was cooled in an ice bath before Tf2O (888 mg, 3 mmol, 1.5 equiv) was added dropwise over 20 min, during which the color changed from deep red to pale orange. Afterwards, the ice bath was removed and the reaction mixture was stirred at rt overnight. A work-up similar to that used in the preparation of 1a and 2a gave an oil that slowly crystallized in vacuo (790 mg, 90%). Recrystallization from heptanes/EtOAc gave compound 7 as clear, tan needles, mp. 104-106° C. (dec.). 1H NMR (CDCl3): δ 7.46 (d, J=8.7 Hz, 2H), 7.03 (d, Jab=16.1 Hz, 1H), 6.91 (d, J=8.7 Hz, 2H), 6.89 (d, Jab=16.3 Hz, 1H), 6.72 (s, 2H), 3.93 (s, 6H), 3.84 (s, 3H); 13C NMR (CDCl3): δ 160.00, 152.69, 138.64, 130.35, 129.59, 128.21, 125.75, 118.92 (q, 1JCF=321.3 Hz), 114.49, 102.94, 56.49, 55.58; 19F {13C} NMR (CDCl3): δ −74.11. Anal. Calcd for C18H17F3O6S: C, 51.67; H, 4.10. Found: C, 51.84; H, 3.97.

Herkunft & Nachweise