Synthesis and Properties of Polyfunctional Cyclic β‐Alkoxy‐α,β‐Unsaturated Ketones Based on 4‐Methylene‐1,3‐dioxolanes

Abstract

New CCl3‐ and CF3‐substituted enones, bearing additional hidden hydroxymethyl functions, were prepared by acylation of 4‐methylene 1,3‐dioxolanes. The synthesized enones are interesting building blocks for agrochemical and medicinal chemistry research. The reactivity of synthesized enones with various amines was studied, and enaminones 13 and 14 were obtained under NH3 interaction; the reaction with aliphatic primary amines afforded enaminones 17 in high yields as equilibrium mixtures of E and Z isomers. The reaction of fluorinated enone 9c with anilines afforded a mixture of products, including non‐aromatic heterocyclic compounds 25 and 26 bearing the CF3 group as well as furan 27 with CF3 and amino functions at positions 5 and 3, respectively. The hydrolysis of enone 9c afforded cyclic compound 11.

Synthesis of Fluorine‐Containing 3‐Aminocyclopent‐2‐enones via Intramolecular Cyclization

“…[a] Previously synthesized compounds. [10] The target new enones 2c-i were obtained in moderate to high yields as off-white liquids and were fully characterized by 1 H, 19 F (if applicable), and 13 C NMR. Compounds 2c,d are quite stable, but gradually turn yellow at room temperature.…”

“…Adding one equivalent of morpholine or diethylamine, respectively, to enones bearing CF 2 X substituents 2c-e, led to the formation of the dihydrofuran-2-ols 5c-e (Scheme 3 and Table 2) as it was previously observed for enones 2a,b. [10] The compound 5c was isolated in pure form as a light-yellow powder. We didn't succeed in isolating compound 5d in pure state as it was formed as resin, and all purification attempts failed.…”

“…ethanolamine, diisopropylamine, dibenzylamine, and N-methylaniline) as a result of their decreased basicity and increased substituent bulkiness. Taking into account our previous results on CF 3 enone 2a (Scheme 1), [10] we treated freshly prepared 5c with an excess of morpholine in an attempt to obtain a more stable product 6c (Scheme 4). Though, not even traces of product 6c were detected in the reaction mixture by 19 F NMR spectroscopy.…”

“…[9] Previously, we have synthesized the enones 2 with CF 3 and CF 2 H substituents and reacted them with different amines. [10] The reaction of the enone 2a with secondary dialkylamines (e.g., ary amines to form fluorine-containing 3-aminocyclopent-2enones via 4-amino-2,3-dihydrofuran-2-ols. The peculiar mechanism involving an intramolecular electrocyclization as a key step is proposed.…”

Synthesis of a Hominal Bis(difluoromethyl) Fragments

“…Fluorination often improves chemical resistance, thermal stability, biological and optical activity. 1 As a result, C-F bonds can be found in a wide variety of pharmaceuticals, 2,3 agrochemicals, pesticides, surfactants, dyes and polymeric materials. 4,5 The unique properties of the fluorine atom have drawn increasing attention to its potential application in the field of organic photovoltaics (OPV), where the introduction of C-F bonds into the monomers of conjugated polymers can significantly improve their performance.…”