On the effect of cyclodextrin on the Z/E-selectivity of Wittig Reactions with semistabilized ylides
作者:Gunnar Westman、Olof Wennerström、Ilona Raston
DOI:10.1016/s0040-4020(01)80315-x
日期:1993.1
The Z/E-selectivity of Wittigreactions between semistabilized ylids and aromatic aldehydes is affected by the addition of host molecules such as cyclodextrins (CD). An increase in the Z-selectivity from 57 to 92% has been reached with DMF as solvent and an increase in the E-selectivity from 67 to 80% has been reached with ethanol as solvent for the same Wittigreaction. Reactions with arenes with bulky
Stereoselective Synthesis of <i>trans</i>-Stilbenes through Silver-Catalyzed Self-Coupling of <i>N</i>-Triftosylhydrazones: An Experimental and Theoretical Study
作者:Qingmin Song、Yue Zhao、Shaopeng Liu、Yong Wu、Zhaohong Liu
DOI:10.1021/acs.orglett.3c01040
日期:2023.5.19
efficiency with excellent stereoselectivity, broad substrate scope, and good functional group tolerance. A plausible mechanism involving nucleophilic attack of in situ generated sulfonium ylides on silver carbene was proposed on the basis of experimental results and DFT calculations, which further indicates that π–π stacking interactions play a dominant role in stereoselectivity control.
The synthesis of (S,S)-1,2-bis(3,5 -di-tert-butylphenyl)ethane-1,2-diol (98.6% ee), which should be useful as a chiral ligand of catalysts in asymmetric inductions, is described.