Triphenylphosphine → 4-Allyl-3,5-dimethyl-benzaldehyde

Participants

Reaction Conditions

Reaction Steps

To a solution of trifluoromethanesulfonic acid 4-formyl-2,6-dimethyl-phenyl ester (3.13 g, 11.1 mmol), bis(triphenylphosphine)palladium dichloride (682 mg, 0.972 mmol), triphenylphosphine (1.76 g, 6.7 mmol), LiCl (3.98 g, 93.8 mmol) and a trace of 2,6-di-tert.-butyl-4-methylphenol in DMF (30 mL), allyltributylstannane (2 mL) is added. The mixture is heated to 120° C. and stirred for 2 h before another portion of allyltributylstannane (2 mL) is added. Stirring is continued at 120° C. for 1 h. The mixture is cooled to rt, diluted with water (100 mL) and extracted with EA. The organic extract is washed with 1.5 M aq. HCl (2×100 mL), dried over MgSO4, and the solvent is evaporated. The crude product is purified by CC on silica gel eluting with heptane:EA 20:1 to give 4-allyl-3,5-dimethyl-benzaldehyde (1.34 g) as a colourless liquid; 1H NMR (CDCl3: δ 9.92 (s, 1H), 7.53 (s, 2H), 5.96-5.80 (m, 1H), 5.06-5.00 (m, 1H), 4.87-4.78 (m, 1H), 3.48-3.40 (m, 2H), 2.38 (s, 6H).

Provenance & Evidence