Fluoride-catalyzed aldol reaction of ethyl trimethylsilyldiazoacetate with aldehydes leading to ethyl α-diazo-β-hydroxy esters and rhodium catalyzed decarboxylative rearrangement of diazo urethanes leading to β-amino acrylates
Ethyl trimethylsilyldiazoacetate reacts smoothly with a variety of aldehydes at 0 degrees C in the presence of a catalytic amount of tetrabutylammonium fluoride to produce alpha-diazo-beta-hydroxy esters in good to excellent yields. The resulting alpha-diazo-beta-hydroxy esters can be,stereoselectively transformed, by a sequence of carbamation with p-toluenesulfonyl isocyanate and rhodium(II)-induced decarboxylative rearrangement, to alpha- or beta-substituted beta-(p-toluenesulfonylamino)acrylates depending upon migration aptitude of the substituents derived from the aldehydes. (C) 1999 Elsevier Science Ltd. All rights reserved.
Deep eutectic solvent (DES) as dual solvent/catalyst for synthesis of α-diazocarbonyl compounds using aldol-type coupling
Deep eutectic solvent (DES) was employed as dual solvent/catalyst in the green synthesis of α-diazocarbonyl compounds using aldol-type coupling. α-Diazocarbonyl compounds are important syntheticintermediates with useful application for synthesis of amino alcohols and acids and many natural products. Moreover, the method is environmentally friendly because of avoidance of toxic solvents or hazardous