Figure 3. Milestones in cross-coupling reactions of aryl ethers and esters.
a, Negishi-type, nickel-catalyzed biaryl formation from aryl ethers (8) and organomagnesium (Grignard) reagents (9). b, Suzuki–Miyaura-type, nickel-catalyzed biaryl synthesis from aryl ethers (8) and boronic esters (10). c, Suzuki–Miyaura-type, nickel-catalyzed biaryl synthesis utilizing aryl esters (11) and aryl boronic acids (12) or aryl boroxines (13). Ph, phenyl; t-Bu, tert-butyl; Et, ethyl; cod, 1,5-cyclooctadiene; i-Pr, isopropyl; Mes, 2,4,6-trimethylphenyl.