Atment of 4 with pivaloyloxymethyl iodide (POMI) (Bandgar et al. 2011) and diisopropylethyl
Atment of four with pivaloyloxymethyl iodide (POMI) (Bandgar et al. 2011) and diisopropylethyl amine (DIPEA) in DMF offered the corresponding bisPOM-protected intermediate (five). Hydrogenolytic removal of amino and carboxyl protecting…