Transition-Metal-Free α-Vinylation of Enolizable Ketones with β-Bromostyrenes

Abstract

An a-vinylation of enolizable ketones has been developed by using b-bromostyrenes and a KOtBu/NMP system. β,γ-Unsaturated ketones of E configuration were obtained in excellent yield and selectivity. Further synthetic possibilities are highlighted by one-pot functionalization via trapping of intermediate dienolates with alkyl, allyl, benzyl, and propargyl halides to generate quaternary centers. The reported transformation is believed to proceed via phenylacetylene and propargylic alcohol intermediates. Regio-and Steroselective 27 Examples, up to 95% yield

Photocatalytic Cross-Coupling of Tetrafluoropyridine Sulfides with Vinyl Halides for the Synthesis of β,γ-Unsaturated Carbonyl Compounds

“…The spectra match the reported literature. 10 Ethyl (E)-4-(o-tolyl)but-3-enoate (5). Compound 5 was prepared following the general procedure.…”

Regioselective Synthesis of 2-Acylbutadienes from β,γ-Unsaturated Ketones

“…termediate with 4-nitrobenzaldehyde (2a) (similar to the recently reported alkylation of ,-unsaturated ketones) 12 were unsuccessful. This is apparently caused by solvent effects since the first stage requires the use of DMSO as a solvent, while the condensation reaction in DMSO under standard conditions (Table 1, entry 4) turned out to be ineffective.…”

“…1 H NMR (400.1 MHz, CDCl 3 ):  (Z-isomer) = 8.09-8.07 (m, 2 H, C 6 H 5 ), 7.53-7.50 (m, 1 H, C 6 H 5 ), 7.42-7.39 (m, 2 H, C 6 H 5 ), 7.34-7.32 (m, 2 H, C 6 H 5 ), 7.28-7.24 (m, 2 H, C 6 H 5 ), 7.18-7.17 (m, 1 H, C 6 H 5 ), 7 12. (d, J = 8.6 Hz, 2 H, ArH), 7.04 (d, J = 16.4 Hz, 1 H, CH=CH), 6.78 (s, 1 H, CH=), 6.48 (d, J = 8.6 Hz, 2 H, ArH), 6.22 (d, J = 16.4 Hz, 1 H, CH=CH), 2.87 (s, 6 H, CH 3 ).…”

Retrosynthetic Analysis of α-Alkenyl-β-Diketones: Regio- and Stereoselective Two-Step Synthesis of Highly Arylated Representatives from Acetylenes, Ketones, and Acyl Chlorides

“…An additional incentive to realize the planned reaction protocol has been provided by the well-documented use of β,γ-unsaturated ketones as carbon nucleophiles in diverse C–C bond forming reactions . Thus, the trapping of the dienolates of β,γ-unsaturated ketones was performed by diverse carbon electrophiles, namely, alkyl halides, aldehydes, , allenamides, di- tert -butyl azodicarboxylate, and alkenes and alkynes activated by nitro, ,, sulphonyl, , or keto groups. , However, an early attempt to couple β,γ-unsaturated ketone with benzoyl chloride in the C-regioselective mode failed, and since then, as far as we know, no more reports have been presented.…”