C-H Functionalization Strategies in the Naphthalene Series: Site Selections and Functional Diversity
Résumé
Naphthalene is certainly not a common arene. In contrast to benzene, the bicyclic feature of naphthalene offers multiple differentiable positions and thus a broad diversity of substitution patterns. Naphthalene is a central building block for the construction of elaborated polycyclic architectures with applications in broad domains such as life and materials sciences. As a result, C-H functionalization strategies specially designed for naphthalene substrates have become essential to install valuable substituents on one or both rings towards polysubstituted naphthalenes. This short review provides a focus on uncommon substitution patterns; however, classical ortho C-H activation is not covered. 1 Introduction 2 C-H Functionalization Using a Directing Group Located at Position 1 2.1 Functionalization on the Ring Bearing the DG: 1,3-Substitution Pattern 2.2 Functionalization on the Ring Bearing the DG: 1,4-Substitution Pattern 2.3 Functionalization on the Neighboring Ring: 1,6-, 1,7- and 1,8-Substitution Patterns 3 C-H Functionalization Using a Directing Group Located at Position 2 3.1 Functionalization on the Ring Bearing the DG: 2,4- and 2,1-Substitution Patterns 3.2 Miscellaneous Substitution Patterns 4 Bis C-H Functionalization 4.1 Symmetrical Bisfunctionalization: 1,2,8-Substitution Pattern 4.2 Symmetrical Bisfunctionalization: 2,3,1-Substitution Pattern 4.2 Unsymmetrical Bisfunctionalization: 2,3,1-Substitution Pattern 4.3 Symmetrical Bisfunctionalization: 2,4,8-Substitution Pattern 5 Conclusion and Outlook