Substrate scope of the cobalt-catalysed Giese reaction of alkyl tosylates with activated olefins^e.

^aReaction conditions: alkyl tosylate (0.25 mmol), activated olefin (0.375 mmol), vitamin B₁₂ (12.5 μmol, 5 mol%), Et₃N·HCl (0.38 mmol), Mn powder (0.75 mmol), DMF (1.5 mL); room temperature for 16 h; the blue-light irradiation; argon atmosphere. Isolated yield.

^bThe reaction was conducted with 5-phenylpenthyl tosylate (5 mmol) and phenyl acrylate (7.5 mmol).

^c5-(tert-Butyldimethylsilyl)-1-chloropenthane was used instead of the corresponding tosylate.

^dReaction time: 24 h.

^e10 mol% of vitamin B₁₂ was used.

^fCo(TMPP) was used instead of vitamin B₁₂.

^gDiastereomeric alkyl tosylate [65 : 35] was used. The values in bracket indicate a diastereomeric ratio of the radical adduct.

^hSee main text.