ABSTRACT
Copper-catalyzed [5+3] cycloaddition of N-aromatic zwitterions and enol diazoacetates produced enantio-enriched diazocine derivatives. A sterically encumbered BOX ligand and NaBArF additive played significant roles in driving the overall catalytic process via the unfavorable dearomatization to construct the desired eight-membered heterocyclic compounds. The induced stereoselectivity was preserved after further modifications of the skeleton, which demonstrates the potential applications of the developed asymmetric catalysis.
Subject(s)
Copper , Heterocyclic Compounds , Catalysis , Cycloaddition Reaction , StereoisomerismABSTRACT
A highly efficient protocol to access carbazole from donor-acceptor cyclopropane and indonyl alcohol via [3+3] annulation in the presence of a Lewis acid has been demonstrated. This method facilitates the post functionalization of the substituted carbazole into a fully conjugated π-system exhibiting intense emission bands in the visible range of the spectrum and also offers a convenient route toward the synthesis of pityriazole derivatives.
ABSTRACT
Lewis acid catalyzed [3 + 3] annulation of N-tosylaziridinedicarboxylates and oxiranes with in situ generated mercaptoaldehyde for the synthesis of functionalized thiazine and oxathiane derivatives has been developed. Additionally, this method facilitates the derivatization of thiazines by detosylation and Krapcho monodecarboxylation.