Anomalous Z-isomer content in Wittig reaction products from keto-stabilised ylides with ortho-heteroatom substituted benzaldehydes
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|Title:||Anomalous Z-isomer content in Wittig reaction products from keto-stabilised ylides with ortho-heteroatom substituted benzaldehydes||Authors:||Byrne, Peter A.
Higham, Lee J.
Gilheany, Declan G.
|Permanent link:||http://hdl.handle.net/10197/4938||Date:||Dec-2012||Online since:||2013-11-19T09:47:33Z||Abstract:||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.||Type of material:||Journal Article||Publisher:||Elsevier||Journal:||Tetrahedron Letters||Volume:||53||Issue:||49||Start page:||6701||End page:||6704||Copyright (published version):||2012 Elsevier Ltd||Keywords:||Wittig reaction mechanism; Keto-stabilised phosphonium ylide; ortho-Substituted benzaldehydes; Kinetic control in Wittig reactions; Z-Alkene; [2+2] Cycloaddition||DOI:||10.1016/j.tetlet.2012.09.123||Language:||en||Status of Item:||Peer reviewed|
|Appears in Collections:||Chemistry Research Collection|
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