Publication Type
Peer Reviewed Journal
Mandatory Citation Fields
Peter A. Byrne, Lee J. Higham, Padraic McGovern, Declan G. Gilheany
2012
December
Tetrahedron Letters
Anomalous Z-isomer content in Wittig reaction products from keto-stabilised ylides with ortho-heteroatom substituted benzaldehydes
Published
Optional Fields
Please enter separate search keywords on separate lines
Wittig reaction mechanism Keto-stabilised phosphonium ylide ortho-Substituted benzaldehydes Kinetic control in Wittig reactions Z-Alkene [2+2] Cycloaddition
53
49
6701
6704
Wittig reaction products of keto-stabilised ylides with ortho-substituted benzaldehydes are found to show significantly higher than expected Z-alkene content (up to 50%) compared to analogous reactions of the same ylides with benzaldehyde itself. A cooperative effect is seen whereby the unusual Z-content is further augmented if the ylide bears greater steric bulk in the α′-position. These results are consistent with our previous observations on reactions of all ylide types with aldehydes bearing a β-heteroatom. Significantly, the cooperative effect, previously seen only with semi-stabilised ylides, has now been extended to stabilised ylides. Both the anomalous increase in Z-content and the cooperative effect can be rationalised within the [2+2] cycloaddition mechanism of the Wittig reaction.
Grant Details
  • © University College Dublin 2010
  • Privacy
  • Policy
  • Freedom of Information