2.3- Difluoroacrylates

The stabilized fluorinated allylic cation, generated from cis- or trans-l-(p-methoxyphenyl)pentafluoropropene and antimony pentafluoride in sulfur dioxide, is solvolyzed by methanol to methyl 2-(p-methoxyphenyl)difluoroacrylate [36] (equation 37)... 

Nitroalcohols undergo addition to isopropyl 2,2-difluorovinyl ketone and isopropyl 3,3-difluoroacrylate in the presence of amines [6] (equation 5)... 

Subsbtuting vinylic hydrogen in a,P-unsaturated carbonyl compounds with vinylic fluonne does not affect their dienophilic character negatively Indeed, 3,3-difluoroacrylic acid is more reactive toward furan than its nonfluonnated counterpart [95] (equation 81) Consistent with this observation is the fact that tctrafluorobenzoquinone forms only a bis-Diels-Alder adduct m 68% yield in its reaction with cyclopentadiene at room temperature [96, 97 ... 

In another approach to 3,3-difluoroacrylate derivatives, Vakselmann and his group (48,49) have taken advantage of the observation that dibromodifluoromethane adds to ynamines (99) (Scheme 30) and enol ethers (102) (Scheme 31) under UV irradiation. Subsequent elaboration of the initial addition products, 100 and 103, derived from N,N-diethyl-l-butynylamine and ethyl vinyl ether afforded 3,3-difluoroacrylamide (101) and 3,3-difluoroacrylate (106), respectively. 

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