Hexafluoro‐2‐propanol‐promoted Intramolecular Friedel‐Crafts Acylation

Abstract

A. 4- (3,butanoyl chloride ( 2). An oven-dried, 250-mL, three-necked, 14/20 round-bottomed flask is equipped with an egg-shaped magnetic stir bar (2 cm), a pressure-equalizing addition funnel (25 mL), a rubber septum, and an argon inlet (Figure 1). The flask is charged with 4-(3,4-dimethoxyphenyl)butanoic acid (1) (7.25 g, 32.3 mmol, 1.0 equiv) (Note 2), anhydrous DCM (40 mL) (Note 3) and DMF (50. µL, 0.65 mmol, 0.02 equiv) (Note 4). Oxalyl chloride (5.5 mL, 64 mmol, 2.0 equiv) (Note 5) is added via syringe to the addition funnel, and the stopcock is opened such that the oxalyl chloride is added over 4 min, resulting in effervescence. The reaction mixture is stirred at 23 °C for 30 min from the start of the addition O OH