The Role of Acetylides in Dual Gold Catalysis: A Mechanistic Investigation of the Selectivity Difference in the Naphthalene Synthesis from Diynes



Under the conditions of dual activation catalysis with oxygen nucleophiles, β-substituted naphthalenes were obtained from 1,2-diethinyl arenes. Mechanistic studies, which include isotope labeling experiments, support that dual activation leads to β-substituted naphthalenes, whereas α-naphthalenes are formed by π activation only, and no gold acetylide or dual activation is involved in the formation of the α-substituted products. Additional experiments on substrates that led to dibenzopentalenes support these mechanistic insights.