Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reactionbetween hydantoins or thiohydantoins and dialkyl acetylenedicarboxylates in the presence oftriphenylphosphine. These phosphoranes undergo smooth intramolecular Wittig reaction followedby an electrocyclic ring opening to produce dialkyl (E)-2-(2,5-dihydro-5,5-diaryl-2-thioxo-1H-imidazol-4-yl)fum...

The (dia-)stereoselective synthesis of glycidic amides and esters has attracted considerable interest over the last few decades mainly due to the high potential of these compounds as synthetically useful intermediates in a variety of organic syntheses. Ylides have proven to be very powerful synthons for the formation of epoxides providing alternatives to the oxidation of a,b-unsaturated carbony...

1,3-Dipolar cycloaddition reactions of azomethine ylides play an important role in the synthesis of highly substituted pyrollidines which are found in the structures of many important natural products and pharmaceuticals . Using this chemistry, four chiral centers can be created in a single step. The asymmetric version of this reaction has been tried both with achiral azomethine ylides and chir...

stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reactionbetween hydantoins or thiohydantoins and dialkyl acetylenedicarboxylates in the presence oftriphenylphosphine. these phosphoranes undergo smooth intramolecular wittig reaction followedby an electrocyclic ring opening to produce dialkyl (e)-2-(2,5-dihydro-5,5-diaryl-2-thioxo-1h-imidazol-4-yl)fum...

In this paper, we describe studies on the cyclopropanation of Michael acceptors with chiral sulfur ylides. It had previously been found that semi-stabilized sulfonium ylides (e.g., Ph-stabilized) reacted with cyclic and acyclic enones and substituted acrylates with high ee and that stabilized sulfonium ylides (e.g., ester-stabilized) reacted with cyclic enones again with high ee. The current st...