2-Methyl-2-phenylpropanal → (S)-N-(2-Methyl-2-phenylpropylidene)-p-toluenesulfinamide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirred solution of 2.5 g of 2,2-dimethyl-3-phenyloxirane (16 mmol) in 85 mL of anhydrous benzene is added 0.415 g (0.362 mmol, 5 mol %) of tris(pentafluorophenyl) borane. The light yellow solution is stirred at 25° C. for 19 hours. The reaction mixture containing the 2-methyl-2-phenylpropanal is then treated with (S)-p-toluenesulfinamide (2.3 g, 15 mmol) followed by a solution of 16 mL (73 mmol) titanium ethoxide in 155 mL of benzene. The yellow solution is stirred at 25° C. for 24 hours then cooled to 5-10° C. and quenched with 245 mL of water. The mixture is filtered through diatomaceous earth, and the filter cake washed with methylene chloride (4×50 mL). The aqueous layer is washed with methylene chloride (1×25 mL). The combined organic layers are dried (MgSO4) and concentrated under reduced pressure to give 3.74 g (81%) of the desired product as a white solid. The product is used without further purification in the next step.

Herkunft & Nachweise