Allenic Esters and Dienoates

Allenic Esters and Dienoates. - The Wittig approach to allenes from phosphoranes and ketenes or equivalents thereof has been 

A range of (, Z)-dienes including dienoic acids (245) are readily obtainably by an extension of the Normant reaction in which lithium dialkylcuprates undergo double incorporation of acetylene to give a dienylcuprate which can be trapped by a variety of reactive electrophiles including CO2 [— (245)], 

7-Aryl-hepta-2,4,6-trienoates (247) have been formed from cinnamaldehydes by coupling with acetylketene dithioacetals 

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