'Salen' along: The iridium(III)–salen complex 1 efficiently catalyzes the title reaction of 2‐ethylbenzenesulfonyl azides to give five‐membered sultams with high enantioselectivity. Other 2‐alkyl‐substitued substrates lead to five‐ and six‐membered sultams with high enantioselectivity; the regioselectivity depends upon the substrate and the catalyst used. EDG=electron‐donating group.
Catalytic Enantioselective Synthesis of 3-Substituted Benzosultams via Corey-Bakshi-Shibata Reduction of Cyclic N-Sulfonylimines
作者:Dieter Enders、Matthias Seppelt
DOI:10.1055/s-0030-1259314
日期:2011.2
The catalytic asymmetric synthesis of 3-substituted benzo-fused sultams employing the Corey-Bakshi-Shibata reduction with catecholborane of the corresponding cyclic N-sulfonylimines is reported. Good to excellent yields (74-95%) and enantiomeric excesses (69-94%) are obtained.
An N-heterocyclic carbene iridium catalyst with metal-centered chirality for enantioselective transfer hydrogenation of imines
作者:Yanjun Li、Meng Lei、Wei Yuan、Eric Meggers、Lei Gong
DOI:10.1039/c7cc04691j
日期:——
carbene iridium complex featuring metal-centered chirality was designed and applied to the asymmetric transfer hydrogenation (ATH) of imines. Four strongly σ-donating carbon-based substituents (2 carbenes and 2 phenyl moieties), a chirality transfer directly from the stereogenic metal center to the C=N bond of substrates, as well as a restriction of catalyst deactivation by steric demanding substituents