Which reagents best accomplish the following transformation

Last updated: 6/15/2023

Which reagents best accomplish the following transformation fer O 1 HOCH CH OH H cat 2 CH3CH MgBr excess 3 H3O O 1 NaOH A 2 CH3CH Br excess 3 H3O O 1 H3O A 2 CH3CH C O CH CH3 O 1 CH3CH MgBr excess 2 PCC HO f