Table 1. Investigation of the steric influence in the lithiation–borylation reaction ^{a , b} .

^aReaction conditions: A: (i) 1.3 equiv. sBuLi, Et₂O (0.3 M), –78 °C, 1 h; (ii) 1.5 equiv. boronic ester in Et₂O (1.0 M), –78 °C, 2 h; (iii) –78 °C → r.t., o/n; B: (i) and (ii) as A; (iii) 1.3 equiv. of MgBr₂ in MeOH (1.0 M), then –78 °C → r.t., o/n.

^bThe ratio of anti to syn diastereoisomers determined by ¹H NMR spectroscopy is shown in parentheses (for details see ESI).

^cYield determined by ¹H NMR spectroscopy with internal standard.

^dTraces of product could be detected by GC/MS but isolation was unsuccessful.