(E)-Trimethyl(perfluoroprop-1-enyl)silane As a Reagent to Transfer Perfluoroprop-1-enyl Group to Ketones and Aldehydes Catalyzed by Fluoride

Abstract

Analogous to trifluoromethyltrimethylsilane (Ruppert’s reagent) (E)-trimethyl(perfluoroprop-1-enyl)silane (1), prepared by deprotonation of (Z)-1,2,3,3,3-pentafluoroprop-1-ene (2a) at −78 °C in the presence of chlorotrimethylsilane, was shown to transfer the perfluoroprop-1-enyl group to a number of electrophiles containing carbonyl group in the presence of catalytic amount of fluoride anion. The perfluoroprop-1-enyl group was transferred to formaldehyde, acetaldehyde, benzaldehyde, acetone, trifluoroacetophenone resulting in formation of corresponding TMS-ethers of secondary and tertiary alcohols containing Z-CF3CFCF– fragment. With some substrates such as hexafluoroacetone, formaldehyde, and trifluoroacetophenone, substituted 5-membered dioxolane products of the reaction can be obtained, depending on the reaction conditions and the source of fluoride catalyst.

Structural Characterization of Hydro‐, Chloro‐ and Fluoroorganylsilanes with Substituents of Varying Electron Withdrawing Character

“…The reaction of lithium reagents 1 a – d with chlorotrimethylsilane in dimethyl ether afforded ( E )‐trimethyl(pentafluoropropen‐1‐yl)silane ( 2 a ), trimethyl(trifluoropropyn‐1‐yl)silane ( 2 b ), trimethyl(pentafluoroethyl)silane ( 2 c ) and trimethyl(trifluorovinyl)silane ( 2 d ). Because of its low boiling point of −24.8 °C [20] dimethyl ether could be easily separated from the silanes (boiling points of 2 a : 94 °C, [21] 2 b : 73–74 °C, [22] 2 c : 69–71 °C, [23] 2 d : 65 °C [10] ) whereas the purification of silanes generated in diethyl ether is sometimes effortful.…”

“…After condensation of all volatile compounds ( E )‐trimethyl(pentafluoropropen‐1‐yl)silane (1.86 g, 9.14 mmol, 63 %) was obtained as a pale yellow liquid. NMR data [21] as in the literature.…”

Application of Industrially Relevant HydroFluoroOlefin (HFO) Gases in Organic Syntheses

“…In the presence of diisopropylamine (DIPA) base (Z)-1,2,3,3,3-pentafluoroprop-1-ene (HFO-1225ye, 42) reacted with chlorotrimethylsilane (TMSCl) to form the corresponding silyl product (85, Scheme 12D). 58 The formed silyl olefins were used as intermediates to aldehydes or ketones through fluoride mediated transformations (from CsF). Besides the substitution, Yagupolskii et al conducted an extensive study in the hydrosilylation reaction of HFOs.…”

“…Remarkably, the deprotonation of (Z)-1,2,3,3,3-pentafluoroprop-1-ene (42) with a lithium organic base did not result the elimination of the vinylic and trifluoromethyl fluoride, hinting at an increased overall anion stability. 59 In the presence of diisopropylamine (DIPA) base, (Z)-1,2,3,3,3pentafluoroprop-1-ene ( 42) reacted with chlorotrimethylsilane to form silyl product 85 (Scheme 12D). 59 The thus formed silyl olefins were used as intermediates to aldehydes or ketones through fluoride-mediated transformations (from CsF).…”

Substrate-Controlled Product Divergence: Silver-Catalyzed Reaction of Trifluoromethyl Ketones with Terminal Alkynes

“…Jeong et al 8 developed a highly stereoselective synthesis of (Z)-isomer products from starting materials in a three-step procedure (Scheme 1, route a). Recently, Larichev and Petrov 9 used ( E )-trimethyl (perfluoroprop-1-enyl)silane as a staring material to produce (E)-isomers (Scheme 1, route b). However, diastereoselectivity of the 1,3-dioxolane ring is not controlled in these two methods.…”