CHIMIA (Apr 2012)
Palladium-NHC Catalyzed Enantioselective Synthesis of Fused Indolines via Inert C(sp3)-H Activation
Abstract
New sterically hindered chiral N-heterocyclic carbene (NHC) ligands were used in palladium catalysis to bring about a highly enantioselective C(sp3)-H activation on the methylene site of a cycloalkane moiety. The intramolecular coupling reaction of a prochiral N-aryl-N-cycloalkyl methyl carbamate required high temperatures (140–160 °C) and afforded highly enantioenriched trans-2,3-fused indolines.
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