1: (i) NBS, Py, AcOH, aq. NaOAc, acetone, (ii) CaCO3, DMF 2: Py, Ac2O / Heating 3: aq. NaBH4 / methanol; tetrahydrofuran 4: cyclohexanone, Al(OiPr)3 / toluene 5: aq. ethanol / (microbiological transformation) View Scheme

1: (i) NBS, Py, AcOH, aq. NaOAc, acetone, (ii) CaCO3, DMF 2: NaOH / methanol / Heating View Scheme

1: (i) NBS, Py, AcOH, aq. NaOAc, acetone, (ii) CaCO3, DMF 2: NaOH / methanol / Heating 3: CrO3, aq. H2SO4 / acetone View Scheme

(i) NBS, Py, AcOH, aq. NaOAc, acetone, (ii) CaCO3, DMF; Multistep reaction;