Fig. 2: The optimization of reaction conditions.

Reaction Conditions: 1a (0.28 mmol, 1.4 equiv), 2a (0.20 mmol, 1.0 equiv), D1 (0.06 mmol, 30 mol%), NaOtBu (0.6 mmol, 3.0 equiv), CaTiO3 (0.8 mmol, 4.0 equiv), DMSO (1.2 mmol, 6.0 equiv) in a stainless-steel jar (10 mL) with two balls (10 mm) in Ar; ball milling conditions: 2.5 h at 30 Hz; yields were determined by GC using dodecane as an internal standard. a The optimization of piezoelectric materials; b The optimization of liquid assisted grinding (LAG); c The optimization of bases; d The optimization of electron donors; e Control experiments; f Solution reactions, rt: room temperature.