Over the last 8 years, our laboratory has developed the concept of iminium catalysis, a mode of LUMO-lowering activation that has enabled the invention of a large number of enantioselective organocatalytic transformations including Diels-Alder cycloadditions, Friedel-Crafts alkylations, Mukaiyama-Michael additions, hydrogenations, and heteroconjugate additions.1 Central to the utility of this t...

The diastereospecific formation of δ-hydroxyalkylbutenolide phosphonate has been achieved via a vinylogous Mukaiyama aldol reaction. The reaction was performed using α-ketophosphonate 1 and 2-(trimethylsilyloxy)furan 2 mediated by Cu(OTf)(2) and 2,2,2-trifluoroethanol as additive in CH(2)Cl(2). The reaction proceeds rapidly and affords the corresponding 5-(hydroxy(aryl)methyl) furan-2(5H)-one p...

Tris(2,3,5,6-tetrathiaaryl)methyl radicals, so-called trityl radicals, are emerging as spin labels for distance measurements in biological systems based on Electron Paramagnetic Resonance (EPR). Here, the synthesis and characterization of rigid model systems carrying either two or three trityl moieties is reported. The monofunctionalized trityl radicals are connected to the molecular bridging s...