Exploring the selectivity of the Suzuki–Miyaura cross-coupling reaction in the synthesis of arylnaphthalenes

A series of 1-arylnaphthalenes and 1,8-diarylnaphthalenes were synthesized by the Suzuki–Miyaura cross-coupling methodology showing significant differentiation in the yields and selectivity between aryl rings with electron donating (higher yields), and electron withdrawing substituents (lower yields). These results strongly support the relation between the nucleophilicity of the boronate complex and its reactivity, and emphasize the importance of the transmetalation step in the overall efficiency of this cross-coupling reaction. The results obtained with non-symmetric 1,8-diarylnaphthalenes indicate preference for arylation of an already arylated species (the 1-aryl-8-bromonaphthalene intermediate) over mono-arylation of 1,8-dibromonaphthalene. Evidences for the existence of intramolecular Pd⋯π and aromatic interactions in some Pd(II) complexes were found.