Trifluoroacetic anhydride-mediated

Already in 2001, Basavaiah and Satyanarayana [49] reported Sj,2 bisalkylation of indanone (68a) or 1-tetralone (68b) with Bayhs-Hillman acetates 30 followed by a saponification and trifluoroacetic anhydride-mediated bis-lactonization of 70 as a facile route to bis-a-aryhdene-S-lactones 71 (Scheme 4.18). Reactions proceeded in... 

A coupling of vindoline (3) with catharanthine A-oxide (45), mediated by trifluoroacetic anhydride, and subsequent reduction with sodium boro-hydride delivered anhydrovinblastine (42) in up to 40% yield, accompanied by minor amounts of the undesired C-16 (R) isomer 24 as well as some 17-deacetylanhydrovinblastine (46) (Scheme 13) (38-41). The struc-... 

A transition metal-mediated approach to amidation of glycal substrates can lead to the formation of 2-deoxy-2-trifluoroacetyl-amido derivatives. Thus, when a solution of (saltmen)Mn(N) is added to a mixture of trifluoroacetic anhydride (TFAA) and glycal 107 followed by sequential treatment with thiophenol and BF3 Et20, the 2-A-trifluoroacetamido thioglycoside 108 can be obtained in good yield and excellent diastereoselectivity (O Scheme 53) [91]. 

Chloro-3-(trifluoroacetyl)coumarm (346) was synthesized via direct TMSCl-mediated acylation of 4-hydroxycouniarin with trifluoroacetic anhydride (TFAA) followed by the treatment with POCI3 [203] (Scheme 111). 

The selective oxidation of C—H bonds in alkanes under mild conditions continues to attract interest from researchers. A new procedure based upon mild generation of perfluoroalkyl radicals from their corresponding anhydrides with either H2O2, m-CPBA, AIBN, or PbEt4 has been described. Oxidation of ethane under the reported conditions furnishes propionic acid and other fluorinated products.79 While some previously reported methods have involved metal-mediated functionalization of alkanes using trifluoroacetic acid/anhydride as solvent, these latter results indicate that the solvent itself without metal catalysis can react as an oxidant. As a consequence, results of these metal-mediated reactions should be treated with caution. The absolute rate constants for H-abstraction from BU3 SnH by perfluorinated w-alkyl radicals have been measured and the trends were found to be qualitatively similar to that of their addition reactions to alkenes.80 a,a-Difluorinated radicals were found to have enhanced reactivities and this was explained as being due to their pyramidal nature while multifluorinated radicals were more reactive still, owing to their electrophilic nature.80... 

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