Rhodium-Catalyzed Asymmetric Allylation of Malononitriles as Masked Acyl Cyanide with Allenes: Efficient Access to β,γ-Unsaturated Carbonyls
A rhodium-catalyzed regio- and enantioselective intermolecular allylation of malononitriles as masked acyl cyanides (MAC) with terminal and symmetrical internal allenes is reported. A RhI/Josiphos catalytic system combined with subsequent oxidative degradation of the primary adducts enables a straightforward access to α-branched, β,γ-unsaturated carbonyl compounds. The present protocol exhibits perfect atom economy in the allylation step and is characterized by a great functional group compatibility. Furthermore, the use of α-substituted malononitriles allowed for the construction of all-carbon quaternary centers.
Grugel, Christian P.,Breit, Bernhard
supporting information
p. 15223 - 15226
(2018/09/25)
Synthesis of new derivatives of copper complexes of Josiphos family ligands for applications in asymmetric catalysis
A series of new copper complexes containing chiral ferrocenyl diphosphine ligands of the Josiphos family have been prepared. These complexes have been studied in the catalytic asymmetric 1,2-addition of Grignard reagents to enones and aromatic ketones. Variation of the electronic and steric properties of the ligand resulted in a positive effect in the regio- and enantioselectivity of Grignard reagents to α-H-substituted enones using the ligand in which tert-butyl substituents were introduced in the diarylphosphine moiety. The copper complexes were also successfully applied in the catalytic asymmetric conjugate addition of Grignard reagents to enoates. No increase of enantioselectivity was observed in the catalytic asymmetric addition of linear Grignard reagents, compared to that of the commercially available ligand rev-Josiphos. The Royal Society of Chemistry 2014.
Oost,Rong,Minnaard,Harutyunyan
p. 1997 - 2005
(2014/06/24)
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