“…[16][17][18] Mild alkyl methyl sulfide (n-BuSMe, PhSMe, n-C 10 H 21 SMe) also only gave low to moderate yields of 24%-58% (Entries 3-5), which might be attributed to the bulky phenyl substitute in the cobalt-alkynl complexes hindering the approach of bulk promoters. [19,20] Thus, a "smaller" promoter DMS (dimethyl sulfide) was used and worked with improved yields (Entries 6, 7), and xylene was also a nice solvent (Entry 8). Since α,β-unsaturated aldehydes/ketones readily undergo 1,2-addition with nitroalkanes under basic conditions, both the activation of carbonyl group and the controlling of proper pH are crucial to gain the Michael addition reaction product.…”