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CAS: 1002357-04-1
MF: C27N2+.I-
MW: 479.2063
Synonyms:

REPORT BY

Masato Ohashi

Osaka University
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Peter Kundig

University of Geneva
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Co-reporter: Dmitry Katayev;Dr. Evgeny Larionov;Dr. Masafumi Nakanishi;Dr. Céline Besnard;Dr. E. Peter Kündig
pp: 15021-15030
Publication Date(Web):
DOI: 10.1002/chem.201403985

Abstract

Two bulky, chiral, monodentate N-heterocyclic carbene ligands were applied to palladium-catalyzed asymmetric C[BOND]H arylation to incorporate C(sp3)[BOND]H bond activation. Racemic mixtures of the carbamate starting materials underwent regiodivergent reactions to afford different trans-2,3-substituted indolines. Although this CAr[BOND]Calkyl coupling requires high temperatures (140–160 °C), chiral induction is high. This regiodivergent reaction, when carried out with enantiopure starting materials, can lead to single structurally different enantiopure products, depending on the catalyst chirality. The C[BOND]H activation at a tertiary center was realized only in the case of a cyclopropyl group. No C[BOND]H activation takes place alpha to a tertiary center. A detailed DFT study is included and analyses of methyl versus methylene versus methine C[BOND]H activation is used to rationalize experimentally observed regio- and enantioselectivities.