To a solution of 305 mg of tert-butyl 3-(2-formyl-3-methylphenyl)propanoate in 3 ml of THF 3 ml were added 298 mg of (S)-2-methyl-2-propanesulfinamide and 0.62 ml of tetraethyl orthotitanate, followed by stirring at room temperature for 16 hours. The reaction mixture was poured into ice water and the insoluble material was filtered through Celite. To the filtrate was added chloroform to carry out a layer separation operation. The organic layer was washed with water and subsequentially with saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography to obtain 336 mg of tert-butyl 3-{2-[(E)-{[(S)-tert-butylsulfinyl]imino}methyl]-3-methylphenyl}propanoate.
