A new organic transformation by introducing crotyl/allyltrifluoroborates in cross-coupling reaction with aroyl chlorides (original) (raw)
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International Journal of Organic Chemistry, 2016
An interesting regioselectivity is observed when the mixture of potassium crotyltrifluoroborate (1a) and aroyl chlorides having electron-deficient and electron-rich groups is microwaved in the presence of palladium-catalyst. In the case of electron withdrawing group with phenyl ring of aroyl chlorides, isomerized α,β-unsaturated compound 3 is the product whereas electron donating group with phenyl ring of aroyl chlorides furnishes α-adduct 4. Similar aroylation reaction is also established for potassium allyltrifluoroborate (1b). In this case, regioselectivity is unaffected with changing electron-rich or electron-deficient groups in phenyl ring of the aroyl chlorides. Reactions proceed with, essentially in same rate, affording the corresponding aryl propenyl ketones (crotonophenones) 5 in good to high yields.
Microwave-Enhanced Cross-Coupling Reactions Involving Alkynyltrifluoroborates with Aryl Bromides
Molecules, 2013
Palladium-catalyzed alkynylation has emerged as one of the most reliable methods for the synthesis of alkynes which are often used in natural product syntheses and material science. An efficient method for coupling alkynyltrifluoroborates with various aryl bromides in the presence of a palladium catalyst has been developed using microwave irradiation. The microwave reactions are rapid and efficient.
Chemical Communications, 2007
General Methods. Difluoroenol silyl ethers 1 2a-2e and monofluoro silyl enol ether 2 4 were prepared as described previously. Tri-n-butyltin fluoride and a 1M toluene solution of P(t-Bu)3, were purchased from Aldrich Chemical Co. and used as received. Toluene was distilled under nitrogen over sodium prior to use. All other chemicals were used as received from commercial sources. 1 H NMR spectra were obtained on a 300-or 500-MHz spectrometer, and chemical shifts were recorded relative to a residual protonated solvent. 13 C NMR spectra were obtained at 75.5 MHz on a 300-MHz instrument, and chemical shifts were recorded relative to the solvent resonance. Both 1 H NMR and 13 C NMR chemical shifts are reported in parts per million relative to tetramethylsilane. 19 F NMR chemical shifts are reported in parts per million from CFCl 3. The solvent was CDCl 3 unless otherwise stated. The purity of products was determined by CH&N elemental analyses. Column chromatography was carried out using ACROS silicagel (0.060-0.200 mm). Thin layer chromatography (TLC) was carried out on commercially available pre-coated plates (Whatman UV 254 silica).