Copper‐Catalyzed Coupling Reaction of Secondary Alkyl 2‐Pyridinesulfonates with Alkyl Lithium‐Based Reagents

Abstract

AbstractThe Cu(OTf)2‐catalyzed alkyl–alkyl coupling reaction of a secondary substrate MeCH(OSO2Py)CH2CH2C6H4(4‐OMe) with a nBuLi‐based reagent prepared by transmetalation with MgBr2 ⋅ THF3 in THF produced a coupling product in 74 % yield. The use of soluble MgBr2 ⋅ THF3 in THF was required for this reaction. This method was applied to sBuLi and Ph(CH2)4Li. In contrast, transmetalation of MeLi with soluble MgCl2 ⋅ THF2 in THF produced the Me reagent, which was reactive for the coupling reaction. The reaction proceeded with inversion of the stereogenic carbon. Furthermore, (S)‐14‐methyloctadecan‐2‐one, a sex pheromone produced by lichen moths, was synthesized.