Controlled-Coupling of Quinone Monoacetals by New Activation Methods: Regioselective Synthesis of Phenol-Derived Compounds

We have studied for a long time the reaction of quinone acetal type compounds, such as quinone monoacetals, quinone O , S -acetals, and iminoquinone monoacetals, and have reported the regioselective introduction of various nucleophiles. Quinone monoacetals show various types of reactivities toward nucleophiles due to their unique structures. In this study, we found that aromatic and alkene nucleophiles can be regioselectively introduced into the -position of the carbonyl group on quinone monoacetals by specific activation of the acetal moiety. These reactions enabled the metal-free synthesis of highly functionalized aromatic compounds by the regioselective introduction of nucleophiles. In this account, we describe our recent studies of the coupling of quinone monoacetals. 1 Introduction 2 Regioselective Introduction of Aromatic Nucleophiles into -Position of Carbonyl 2.1 Biaryl Synthesis by Introduction of Aromatic Nucleophiles 2.2 Synthesis of Terphenyls and Oligoarenes by Iterative Coupling 2.3 Synthesis of Phenol Cross-Coupling Products 3 [3+2] Coupling with Alkene Nucleophiles 3.1 Development of Efficient [3+2] Coupling 3.2 Improvement of BrOnsted Acid Promotor 4 Synthesis of -Aryl Carbonyl Compounds Triggered by Silyl Transfer 5 Utilization of o -Quinone Monoacetals 6 Application to Iminoquinone Monoacetals 7 Conclusion