Selected results for the optimal reaction conditions^a.

Entry	Product	Yieldb (%)
1		92
2		94
3		93
4		93
5		91
6		92
7		93
8		95
9		92
10		91
11		85
12		76
13		87
14		93
15		55
16		91

^aReaction conditions: ArGeMe₃1 (0.65 mmol), aldehyde 2 (0.5 mmol), CoI₂ (3.9 mg, 2.5 mol%), tmphen (L8, 3.0 mg, 2.5 mol%), K₂CO₃ (138 mg, 1.0 mmol), THF (3 mL), 65 °C for 12 h, under air in pressure tubes.

^bYields of isolated products after chromatography.