To a solution of 3-{[5-(diethoxy-phosphoryl)-thiophen-2-yl]-hydroxy-methyl}-5-isopropoxy-benzoic acid (700 mg, 1.64 mmol) in CH2Cl2 (10 ml) was added TFA (1.1 ml), followed by triethylsilane (0.92 ml, 5.72 mmol). The reaction mixture was then stirred at r.t. for 30 min, concentrated down, re-dissolved in water, extracted with EtOAc. The EtOAc layer was separated, dried over MgSO4, filtrated, and concentrated to afford the crude product 3-[5-(diethoxy-phosphoryl)-thiophen-2-ylmethyl]-5-isopropoxy-benzoic acid.
