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. 2022 Jan 14;24(1):441-445.
doi: 10.1021/acs.orglett.1c04135. Epub 2021 Dec 14.

Regio- and Enantioselective Iridium-Catalyzed Amination of Alkyl-Substituted Allylic Acetates with Secondary Amines

Woo-Ok Jung  1 , Minjin Yoo  1 , Madyson M Migliozzi  2 , Jason R Zbieg  2 , Craig E Stivala  2 , Michael J Krische  1
Affiliations

Regio- and Enantioselective Iridium-Catalyzed Amination of Alkyl-Substituted Allylic Acetates with Secondary Amines

Woo-Ok Jung et al. Org Lett. .

Abstract

Robust air-stable cyclometalated π-allyliridium C,O-benzoates modified by (S)-tol-BINAP catalyze the reaction of secondary aliphatic amines with racemic alkyl-substituted allylic acetates to furnish products of allylic amination with high levels of enantioselectivity. Complete branched regioselectivities were observed despite the formation of more highly substituted C-N bonds.

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Figures

Figure 1.
Figure 1.
Cationic vs neutral chiral iridium complexes for regio- and enantioselective allylic amination.
Scheme 1.
Scheme 1.
Comparison of SEGPHOS- and tol-BINAP-modified π-allyliridium-C,O-benzoate catalysts for asymmetric allylic aminations employing secondary aliphatic amine nucleophiles.a aYields are of material isolated by silica gel chromatography. Enantioselectivity was determined by chiral stationary phase HPLC analysis. See Supporting Information for further experimental details.
Scheme 2.
Scheme 2.
Iridium-catalyzed amination of branched alkyl substituted allyl acetates 1a-1j with secondary aliphatic amines 2a-2t to form enantiomerically enriched allylic amines 3a-3ab. Yields are of material isolated by silica gel chromatography. Enantioselectivity was determined by chiral stationary phase HPLC analysis. See Supporting Information for further experimental details.
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