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44.1.4.1.2.11.1 Variation 1: Wittig Reaction of Aldehydes or Ketones with Allenylidenephosphoranes

DOI: 10.1055/sos-SD-044-00002

Ogasawara, M.Science of Synthesis, (20084446.

The Wittig reaction has been applied to the preparation of [3]cumulenes. Since butatrienes possess three C=C bonds in a molecule, several approaches are possible for constructing C=C=C=C skeletons. Most Wittig butatriene preparations are reactions between aldehydes or ketones and allenylidenephosphoranes 132, which are usually generated in situ and reacted with the carbonyl compound directly, to give butatrienes 133 in good yields (Scheme 58).[‌127‌‌130‌] Very reactive bromo[3]cumulenes are also generated by this method and used for further transformations without isolation.[‌131‌‌133‌]

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