The product of Step 2 (5.1 g) in CH2Cl2 (50 mL) was treated sequentially with trifluoroacetic acid (8.9 mL) and triethylsilane (34.5 mL). After 18 h, the solution was treated with saturated NaHCO3 (150 mL). After a further 1 h, the organic layer was separated and the aqueous extracted with CH2Cl2 (100 mL). The organic extracts were combined, dried over Na2SO4, filtered and evaporated. The crude product was purified by silica gel chromatography, eluting with EtOAc/hexane mixtures to give 1-benzyloxycarbonyl-4(2-methylthiophenyl)piperidine (3.3 g).
