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A. Synthesis of ethyl 4-((tert-butyldimethylsilyl)oxy)cyclohexanecarboxylate. Under dry conditions, tert-butyldimethylchlorosilane (10.6 g, 70 mmol) and imidazole (9.9 g, 145 mmol) were dissolved in N,N-dimethylformamide (DMF, 20 mL). Subsequently, ethyl trans-4-hydroxycyclohexanecarboxylate (9.4 mL, 58 mmol) was added to this solution. The reaction mixture was stirred at 35 °C for 12 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate (EtOAc, 100 mL) and washed with deionized water (3 × 100 mL). The organic phase was dried with anhydrous sodium sulfate (Na2SO4), filtered and concentrated to give the white solid product ethyl 4-((tert-butyldimethylsilyl)oxy)cyclohexanecarboxylate (16.6 g, quantitative yield). The product did not require further purification and could be used directly in subsequent steps.

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