Chiral ylide

It is interesting to note that the reaction of trans-henzal-acetophenone with ylide 162a affords (15, 25 )-phenylcyclopropane with 35.3% optical purity, whereas its enantiomer having the (li ,2/ )-configuration is formed when tranj-benzalacetophenone is reacted with ylide 162b. Studies on the relationship between the steric requirements of the substituents attached to the chiral ylide sulfur atom and the optical purity of the cyclopropane rings formed have shown that increases in the steric size of the iV,iV-dialkylamino... 

It is interesting to note that asymmetric induction was also observed (308) during generation of ylide 288 from achiral sulfonium salt 287a by means of chiral lithium 2,2,2-trifluoromethyl-a-phenylethoxide. The [2,3]sigmatropic rearrangement of the chiral ylide 288 obtained in situ in this way leads to optically active sulfide 289 of 5% optical purity. 

Chiral Ylides Stereocontrol by Inherent Molecular Structure. 200... 

Chiral Ylides Derived from Asymmetric Templates and Auxiliaries. 208... 

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