Conditions and reagents: (i) 2-Naphthoyl chloride, trans-4-aminocyclohexanol, triethylamine, DCM. (ii) PCC, DCM, room temperature, 12 h. (iii) Allylmagnesium bromide, THF, −78 °C, 2 h. (iv) OsO4, NaIO4, THF–H2O, room temperature, 30 min. (v) Compound 22, NaBH(OAc)3, CH3CO2H, DCM. (vi) Compound 23, NaBH(OAc)3, CH3CO2H, DCM.