Ethyl nosyloxycarbamate

In 2004, Fioravanti, Pellacani, and Tardella reported the asymmetric aza-Michael-initiated ring closure additions of ethyl nosyloxycarbamate to 2-(phenylsulfanyl)-2-cycloalkenones using the cinchona-based PTCs 11 or 29, affording the corresponding aziridines with moderate ee values (Scheme 5.25) [31]. Interestingly, this reaction afforded the same enantiomer, regardless of which pseudoenantiomer of the cinchona-derived catalyst was employed. However, the absolute configuration of the products was not determined in this study. 

Aziridination of a-trifluoromethyl-substituted acrylates such as 137 can be accomplished with ethyl nosyloxycarbamate. With a weak base such as calcium oxide, a Michael adduct is obtained (138), but with sodium hydride Michael addition is followed by cychzation with extrusion of nosylate ion to give 139. ... 

The first organocatalytic asymmetric aziridination reactions of electron-deficient olefins made use of either (i) a chiral tertiary amine combined with a 0-phosphinyl or sulfonyl hydroxylamine for the in situ generation of aminimides as aziridination reagents [133, 134], or (ii) a quaternary salt of cinchona alkaloids in phase-transfer catalysis in combination with ethyl nosyloxycarbamate [135], A-acyl A-aryl... 

Synthesis of 2,3-dihydroquinazolinones has been achieved with 80-98% ee through intramolecular amidation of imines catalysed by Sc(ll)-mrffl-pybox (Scheme 12). The bisaziridination reaction of symmetric (E-s-trans-E)-a-aminating agent occurs diastereospecifically as the aza-anion attacks opposite faces of the conjugated system to form (11) (Scheme 13). °... 

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