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35.1.5.1.12.2.3 Asymmetric Catalytic Aminochlorination of α,β-Unsaturated γ-Oxo Esters

DOI: 10.1055/sos-SD-135-00173

Wirth, T.; Singh, F. V.Science of Synthesis Knowledge Updates, (20171419.

In 2011, Feng and co-workers reported an asymmetric catalytic aminochlorination of α,β-unsaturated γ-oxo esters 40 using N,N-dichloro-4-toluenesulfonamide/4-toluenesulfon­amide (1:1) as reagent and the complex (1:1) of ligand 39 and scandium(III) trifluoromethanesulfonate as catalytic system in dichloromethane (Scheme 21). The reaction products 41 are isolated in excellent yields with up to 99% ee and dr >99:1.[‌46‌] It was demonstrated from mechanistic studies that N-chloro-4-toluenesulfonamide, formed in situ from N,N-dichloro-4-toluenesulfonamide and 4-toluenesulfonamide, is the key reactive species in this catalytic approach.[‌46‌]

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