Multitopic chiral copper complexes based on bis(oxazoline) have been applied in the enantioselective α‐hydrazination of β‐ketoesters. High yields and excellent enantioselectivities were obtained. Furthermore, the catalyticsystems have been recovered in up to ten cycles without loss of activity or enantioselectivity. The formation of coordination polymers [polytopic ligand–Cu]n has been confirmed by UV/Vis
(4+3) Annulation of Donor‐Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones
作者:Stefano Nicolai、Jérôme Waser
DOI:10.1002/anie.202209006
日期:2022.9.5
Azepanones are important and widespread seven-membered heterocycles, but their synthesis is challenging. A convergent method to access these scaffolds was developed relying on a (4+3) annulation reaction of azadienes and donor-acceptor cyclopropanes. Good to excellent yields and high diastereoselectivity were achieved using Yb(OTf)3 as the catalyst. Asymmetric induction was possible with Cu(OTf)2 in
Ligand-Accelerated Asymmetric [1,2]-Stevens Rearrangment of Sulfur Ylides via Decomposition of Diazomalonates Catalyzed by Chiral Bisoxazoline/Copper Complex
Abstractmagnified imageThe first example of catalytic asymmetric [1,2]‐Stevens rearrangement reaction of 1,3‐oxathiolanes with diazomalonates has been developed and up to 90% ee is achieved by the bisoxazoline 4e/copper(II) triflate [Cu(OTf)2] complex.