The Cu(OTf)2-catalyzed alkyl-alkyl coupling reaction of secondaryalkyl sulfonates with RLi-based reagents prepared by transmetalation with soluble MgBr2 ⋅ THF3 in THF proceeded with inversion of the configuration. RLi examined were nBuLi, sBuLi, and Ph(CH2)4Li. In contrast, soluble MgCl2 ⋅ THF2 in THF was suited for MeLi. (S)-14-Methyloctadecan-2-one, a sex pheromone produced by lichen moths, was