Procedure:  100 mL 1-neck flask, stirbar, septum, N₂ inlet

                  Dissolved 0.704 g of I in 30 mL of dry CH₂Cl₂.  Stirred at rt and added 1.50 mL of Et₃N followed by 0.47 mL of pivaloyl chloride (II).  The mixture was stirred for 1 h and then 0.448 g of V was added.  After 16 h, TLC (10:90 EtOAc-hexanes, UV) showed product spot at Rf 0.49.  The reaction mixture was poured into water and extracted with CH₂Cl₂.  The organic layer was dried over MgSO₄, filtered and the solvent was removed by rotary evaporation.  The product was isolated by flash chromatography on silica gel using 1:9 EtOAc-hexanes as eluant.  The product was a clear, colorless oil. 

 

¹H NMR (CDCl₃, 300 MHz) d 8.64 (b, NH), 7.16 (dd, J = 8.8, 1.6 Hz, ArH), 6.57 (m, ArH), 4.31 (q, J = 6.6 Hz, H2), 1.45 (d, J = 6.6 Hz, CHCH₃), 0.97 (s, SiC(CH₃)₃), 0.16 (s, SiCH₃), 0.14 (s, SiCH₃). 

 

notes