Cobalt-Salen Catalyzed Electroreductive Alkylation of Activated Olefins

Table 1

Results of the reductive coupling reaction of 2-bromooctane with methylvinylketone with various cobalt complex catalysts.

Run	Catalyst	Yield^a (%)
1	—	2
2	CoCl2 (5%)	8
3	CoCl2 (5%) + H2Salen (5%)	51^b
4	CoSalen^c (5%)	43
5	CoCl2 (5%) + 2, 2′-bipyridine (5%)	24
6	CoCl2 (5%) + phenantroline (10%)	20
7	CoCl2 (5%) + ephedrine (10%)	56

Experimental conditions: anode = Fe; cathode = Ni grid (surface area = 30 cm²); current intensity I = 0.1 A; solvent = DMF + TBABr (10⁻² mol·L⁻¹) + TBAI (8.10⁻³ mol·L⁻¹); T = 60°C; 2-bromooctane = 0.1875 mol·L⁻¹; methylvinylketone = 0.47 mol·L⁻¹; ^aGC yield, with ethyl undecanoate as internal standard; ^bat 20°C, yield = 27%; at 80°C, yield = 61%; ^cfrom Sigma-Aldrich.