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Updated: Aug 13, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Stereopure Functionalized Benzosultams via Ruthenium(II)-Catalyzed Dynamic Kinetic Resolution-Asymmetric Transfer
Marko Jeran1, Andrej Emanuel Cotman1, Michel Stephan1
1National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia.
Abstract:
A highly diastereo- and enantioselective Ru(II)-catalyzed dynamic kinetic resolution-asymmetric transfer hydrogenation (DKR-ATH) of α-(N-sulfonylimino) and α-(N-sulfonylamino) aryl ketones to 4-hydroxy-benzo-δ- and 3-(α-hydroxy-arylmethyl)-benzo-γ-sultams is presented. By employing enantiopure ansa-Ru[PipSO2DPEN(CH2)4Ph] cat. II with S/C = 10 000 in a HCO2H/Et3N binary mix, up to >99.9% ee and dr >99:1 are obtained with 100% conversion under mild conditions. Application to access the stereopure "structurally simplified TsDPEN" N,N-ligand syn-3-(α-aminobenzyl)-benzo-γ-sultam ("syn-ULTAM") and its structural isomer trans-4-amino-3-phenyl-benzo-δ-sultam (trans-4) is demonstrated.
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