Enantioselective aromatic Claisen rearrangement of allyl 2-naphthyl ethers catalyzed by π-Cu(ii) complexes

Lu Yao; Kazuki Takeda; Kaori Ando; Kazuaki Ishihara

doi:10.1039/d2sc06771d

Enantioselective aromatic Claisen rearrangement of allyl 2-naphthyl ethers catalyzed by π-Cu(ii) complexes

Chem Sci. 2023 Jan 20;14(9):2441-2446. doi: 10.1039/d2sc06771d. eCollection 2023 Mar 1.

Authors

Lu Yao¹, Kazuki Takeda¹, Kaori Ando², Kazuaki Ishihara¹

Affiliations

¹ Graduate School of Engineering, Nagoya University B2-3(611) Furo-cho, Chikusa Nagoya 464-8603 Japan ishihara@cc.nagoya-u.ac.jp.
² Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University Gifu 501-1193 Japan ando@gifu-u.ac.jp.

Abstract

The first catalytic enantioselective aromatic Claisen rearrangement of allyl 2-naphthyl ethers using 5-10 mol% of π-copper(ii) complexes is reported. A Cu(OTf)₂ complex with an l-α-homoalanine amide ligand gave (S)-products in up to 92% ee. Conversely, a Cu(OSO₂C₄F₉)₂ complex with an l-tert-leucine amide ligand gave (R)-products in up to 76% ee. Density-functional-theory (DFT) calculations suggest that these Claisen rearrangements proceed stepwise via tight-ion-pair intermediates, and that (S)- and (R)-products are enantioselectively obtained via the staggered transition states for the cleavage of the C-O bond, which is the rate-determining step.