α-Vinylation of amides with arylacetylenes: synthesis of allylamines under metal-free conditions

Abstract

A novel methodology for the α-vinylation of amides with arylacetylenes under metal-free conditions has been introduced. This methodology provides a new protocol to synthesize allylamines. In each product, the amount of the cis-isomer was more than that of the trans-isomer.

Transition Metal-Free Oxidative Cross-Coupling Reaction of Activated Olefins with N-Alkyl Amides

“…N -cinnamyl- N -methylacetamide (3aa) was obtained as pale-yellow oil (32.9 mg, 87%); purification by silica gel chromatography ( R f = 0.19 eluent: PE/EA = 1:1); 1 H NMR (400 MHz, CDCl 3 - d ): δ 7.41–7.19 (m, 5H), 6.48 (dd, J = 15.8, 9.8 Hz, 1H), 6.20–6.07 (m, 1H), 4.18–4.12 (m, 1H), 4.08–4.05 (m, 1H), 2.99 (s, 1.4H), 2.98 (s, 1.6H), 2.14 (s, 1.4H), 2.13 (s, 1.6H) ppm; 13 C­{ 1 H} NMR (100 MHz, CDCl 3 - d ): δ 170.8, 170.4, 136.5, 136.0, 132.7, 131.7, 128.6, 128.5, 127.9, 127.6, 126.3, 126.0, 124.5, 123.6, 52.5, 49.2, 35.4, 33.4, 21.8, 21.2 ppm.…”

“…A compromise strategy was to utilize activated olefins as radical acceptors, such as the reported cinnamic acids or alkenyl sulfones, which couples with N -alkyl amides to form N -allylic amides in the presence of metals or photocatalysts (Scheme b,c). Moreover, arylacetylene as a coupling partner to react with amides was also developed, although this reaction could give E / Z - N -allylic amides (Scheme d) and as a synthetic precursor for construction of other useful molecules .…”

Catalytic nucleophilic addition of terminal alkynes to α,β-unsaturated-γ-lactams

“…Cyclic N-acyliminium ions are highly reactive electrophiles, which have been used extensively for the construction of nitrogen-containing ring systems via C-C bond-forming reactions [24][25][26][27][28][29]. For example, the research groups of Jacobsen and Dixon independently reported the successful use of this strategy for the installation of pyrrolidinone moieties at the C2-and C3-positions of an indole ring, respectively [30][31][32].…”

Functionalization of Amides via Copper-Catalyzed Oxyalkylation of Vinylarenes and Decarboxylative Alkenylation of sp3 C–H

“…Despite significant developments, syntheses of allylic amides and N -(3-oxoalkyl) amides by sp 3 C–H functionalization of N -alkyl amide remain challenging. Previous methods for allowing access to allylic amides were through the addition reactions of the sp 3 C–H bond into alkynes and either involved a costly iridium complex or afforded an undesirable mixture of E/Z isomers . In the long run, our group and others have been devoted to the cheap, metal-catalyzed sp 3 C–H functionalization related to cinnamic acids and olefins in recent years.…”