Enantioselective Synthesis of Cyclohepta[b]indoles via Pd-Catalyzed Cyclopropane C(sp3)-H Activation as a Key Step

An enantioselective synthesis of functionalized cyclohepta[b]indoles via Pd-catalyzed cyclopropane C-H activation followed by olefination and indole-vinylcyclopropane rearrangement is reported. The design of the chiral cyclopropane precursor was such that both enantiomeric cyclohepta[b]indoles were accessed from a single compound exhibiting a "hidden" symmetry plane. The scope of the method was demonstrated by varying the substituents on the cyclopropane as well as on the heterocycle itself.