Preparation and Reactions of 1 H, ωF1-1-lodoperfluoro-1-alkenes

Abstract

Preparation of R_fCF=CHI [2 a-c] (Rf; a: HCF₂, b: H(CF₂)₃, c: H(CF₂)₅) by the reactions of R_fCF₂CH₂l [1a-c] with the various bases and the reactions of [2] with nucleophi les, metals, and organornetallic compounds were investigated.
[2a] was synthesized in a good yield (80%) by the reaction of [1a] with potassium hydroxide in a mixed solvent of water and DMSO (1: 4), and [2b] and [2c] were also ob tained in 83. --89% yields by the reactions of [1b] and [1c] with sodium methoxide in a mixed solvent of ethanol and DMSO (1: 1) (see Table 1). The configuration of [2] thus obt ained was only Z-form.
[2a] reacted with RONa (R =CH3, C2H5, CF3CH2) at room temperature in DMSO to give 1 H, ωH-1-iodo-2-alkoxyperfluoro-1-alkenes [5a] in 70-73% yields and not to give 1 H, ωH-1-alkoxyperfluoro-1-alkenes. However, the reactions of [2] with RSNa gave only [7], which was brought about by exchanging both of fluorine and iodine bonded to the olefin ic carbons of [2] with two RS groups.
[2] were treated with two e quivalents of Grignard reagent, followed by adding benzaldehyde to afford the corresponding 2-alkyn-1-ol [9] and similarly, by adding carbon dio xide to give the corresponding carboxylic acid [10] in good yields, respectively.
The ultrasonic-assisted carboxylation of [2] and [5a] with carbon dioxide in the presence of zinc gave the corresponding polyfluorinated α, β-unsaturated carboxylic acids, [11] and [12a] D, in considerable yields, respectively. This reaction proceeded stereospecifically with retention of the configuration of the starting materials.