| Popis: |
This chapter covers recent advances in catalytic, asymmetric dearomatization reactions that proceed by cycloaddition. Despite its high stability, which renders it challenging to dearomatize via cycloaddition, Buchner and coworkers discovered the cyclopropanation of benzene in 1896. The unique chemistry of indoles, which possesses reactivity analogous to enamines but are hydrolytically stable, has resulted in their extensive use in the development of cycloaddition and formal cycloaddition reactions. Donor-acceptor cyclopropanes have also been explored as dipoles in asymmetric [3 + 2] cycloaddition reactions. Few examples of asymmetric dearomatization via [3 + 3] cycloaddition reactions have been reported in the literature. Metal-catalyzed carbenoid cyclopropanation has also been explored in heterocyclic arenes. Reiser and coworkers reported Cu/chiral bis(oxazoline)-catalyzed [2 + 1] enantioselective cycloadditions between acceptor-substituted carbenoids (diazoacetates 19 and 23) and furans 18 or W-Boc-pyrrole 22. Over the past three decades, significant progress has been made in the development of new, catalytic asymmetric cycloaddition reactions of arenes. |
