An Efficient and Reliable Catalyst System Using Hemilabile Aphos for B‐Alkyl Suzuki–Miyaura Cross‐Coupling Reaction with Alkenyl Halides

The 9‐methoxy‐9‐borabicyclo[3.3.1]nonane‐based B ‐alkyl Suzuki–Miyaura cross‐coupling reaction (the 9‐MeO‐9‐BBN variant) has been efficiently performed by using the catalyst consisting of Pd(OAc) 2 and a hemilabile P,O‐ligand, Aphos‐Y, under mild reaction conditions (K 3 PO 4 · 3H 2 O, THF/H 2 O, room. temp.). For applications in the total synthesis of structurally complex natural products, the Johnson protocol commonly uses two ligands (dppf and Ph 3 As) and two organic solvents (THF and DMF). In contrast, the new version reported here employs one ligand (Aphos‐Y) and one organic solvent (THF). Moreover, the broad substrate scope and the excellent functional group tolerance of the Pd(OAc) 2 –Aphos‐Y catalyst have been demonstrated, providing a reliable and simple synthetic tool for fragment coupling in total synthesis through formation of a C(sp 3 )–C(sp 2 ) bond.