Asymmetric Bromoamination of Chalcones with a Privileged N,N′‐Dioxide/Scandium(III) Catalyst

Abstract

Choice of metal tips: A scandium(III) complex of a chiral N,N′‐dioxide ligand demonstrated excellent regio‐, diastereo‐, and enantioselectivity, as well as exceptionally high activity in the first catalytic asymmetric bromoamination of chalcone derivatives (see picture). The products, α‐bromo‐β‐amino ketones, have synthetic utility.

Recent progress in enantioselective synthesis of C3-functionalized oxindoles: rare earth metals take action

“…89,90 Hetero-ene reaction To date, the N,N 0 -dioxides L2-L5 have proved useful to accommodate various RE metal ions. 91,92 In the enantioselective hetero-ene reaction of isatins with alkyl enol ethers 33 (Scheme 10), Feng and coworkers found that this reaction proceeded sluggishly in the presence of rare earth metal complex catalysts, such as Yb(OTf) 3 or Sc(OTf) 3 complex catalysts of N,N 0 -dioxide. Gratifying results have been achieved showing that the complexation of N,N 0 -dioxide L3 with Mg(OTf) 2 , which is a kind of important and promising alkaline metal salt characterized by abundance and low toxicity, was efficient.…”

Micelle Enhanced Auto-Oxidative Hydroxysulfenylation of Alkenes

“…Difunctionalization of olefins has received continuous interest as it provides a synthetically useful route to introduce vicinal substituents. − Among them, hydroxysulfenylation of olefins is one of the most versatile and convenient pathways toward simultaneous C–O and C–S bond formation affording β-hydroxysulfides in one pot. − …”

Asymmetric Catalytic Halofunctionalization of α,β-Unsaturated Carbonyl Compounds

“…When our group realized the powerful coordination ability of chiral N , N ′-dioxides with metal salts, we became interested in chiral Lewis acid promoted enantioselective haloamination of enones . Initially, the bromoamination reaction of chalcone with TsNH 2 and NBS was tested by the use of the metal complexes of chiral ligand L-PiPh (Scheme ).…”