Scheme 4. Scope of stereoselective synthesis of hindered tertiary neopentyl boronic esters. Reaction conditions: 1 equiv. carbamate, 1.3 equiv. sBuLi, Et2O (0.3 M), –78 °C, 1 h; 1.5 equiv. boronic ester in Et2O (1.0 M), 3 h; then –78 °C → r.t., o/n. The ratios of enantiomers and diastereoisomers were determined by chiral HPLC.
