SYNTHESIS AND PROPERTIES OF 2-TRIFLUOROMETHYL-SUBSTITUTED 4-PENTENOIC AND 3,4-PENTADIENOIC ACIDS AND THEIR ESTERS
The hydrolysis of the acid fluorides of 2-fluorocarbonyl(methoxycarbonyl)-2-trifluoromethyl-4-pentenoic acids (I) and (II), and of 2-fluorocarbonyl(methoxycarbonyl)-2-trifluoromethyl-3,4-pentadienoic acids (III) and (IV) gave, under mild conditions, 2-trifluoromethyl-4-pentenoic acid (V) and 2-trifluoromethyl-3,4-pentadienoic acid (VII) or their methyl esters (VI) and (VIII).The reactivity of these compounds was studied.
Fluorinated butanolides and butenolides - Part 9. Synthesis of 2-(trifluoromethyl)butan-4-olides by Wittig reaction using methyl 3,3,3-trifluoropyruvate
2-(Trifluoromethyl)butan-4-olides 13 and 14 were prepared by a three-step synthesis starting from a Wittig reagent and methyl 3,3,3-trifluoropyruvate (1) as a building block. The Wittig reaction of (2-oxoalkyl)triphenylphosphonium bromides with pyruvate 1 gave intermediate 4-oxobutenoates 8 and 9, which were stepwise selectively reduced with zinc borohydride firstly at the double bond and subsequently at the oxo group to afford unstable 4-hydroxy-2-trifluoromethylalkanoates 11 and 12, which cyclised spontaneously to the end butenolides 13 and 14.
A one-step photocatalytic synthesis of 2-(trifluoromethyl)butyrolactones
An efficient one-step procedure is described for the synthesis of 2-(trifluoromethyl)butyrolactone 1 and 4-substituted 2-(trifluoromethyl)butyrolactones by the photocatalytic conjugate addition of primary and secondary alcohols to 2-(trifluoromethyl)acrylic acid 6. With the exception of methanol, the reactions are conducted without a photosensitiser. The diastereoisomers of compounds 8 and 10 were separable by chromatography and their relative configurations were established unambiguously by X-ray analyses of suitable crystals.
Reineke, Ninja,Zaidi, Naveed A.,Mitra, Manju,O'Hagan, David,Batsanov, Andrei S.,Howard, Judith A. K.,Naumov, Dmitri Y.
p. 147 - 150
(2007/10/03)
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