Methoxymethyl-triphenylphosphonium chloride → 3-Methyl-4-(4-methylphenyl)-3-pyridin-3-ylbutanal

Under N2 Lithium bis(trimethylsilyl)amide solution (10.5 ml, 10.5 mmol, 1.0M in THF) was added to a mixture of methoxy methyltriphenyl phosphonium chloride (3.43 g, 10 mmol) in 25 ml THF dropwise at 0° C. After 15 min, it was added to a solution of the product of STEP 4 (1.65 g, 6.5 mmol) in 15 ml THF at 0° C. The reaction was stirred for 1 h and quenched with brine. The product was extracted with ethyl acetate. The organic layer was concentrated. The residue was dissolved in 50 ml THF and 50 ml 2N HCl solution. The reaction was stirred at room temperature for 18 h, and THF was evaporated. The residue was dilute with ethyl acetate and basified with 1N NaOH solution. The product was extracted thoroughly with ethyl acetate. The organic layer was washed with brine, and dried with MgSO4, and concentrated. The residue was purified by chromatography (on silica gel, ethyl acetate/hexane=3/1) to yield a brown oil in 1.37 g. NMR spectra of the product were consistent for the proposed structure.