Background and overview[1][2]
Currently, people have conducted extensive research on changes in functional groups in organic compounds, mastered a large number of rules and methods, and achieved many research results with application value. However, relatively little is known about the ubiquitous changes in C—H bonds in organic compounds, and there are even fewer valuable research results. This is because the C—H bonds in organic compound molecules are inactive and it is difficult for chemical reactions to occur.
Looking for suitable transition metal complexes as catalysts, which can successfully break C—H bonds for functionalization. For decades, chemists have conducted a lot of research work in order to find this kind of catalytic complex. But there are many drawbacks to these jobs. In most cases, in order to obtain good catalytic conversion rates, a large excess of raw materials (often solvents) or light must be used, and the catalytic efficiency and chemical yield of the product are generally not high.
In 1993, Murai and his research team discovered and subsequently conducted extensive research on a very effective catalytic addition reaction – the addition of carbonyl groups in aromatic ketone molecules under the catalysis of ruthenium compound RuH2(CO)(PPh3)3 Ortho C—H bond is added to an alkene molecule:
This catalytic reaction has the following characteristics: (1) High yield: The chemical yield based on aromatic ketones is very high, often close to a quantitative reaction, even when equal amounts of ketones and alkenes are used, in most cases The yield is almost quantitative. (2) High efficiency: 1 mol of ruthenium complex can produce 50 mol of product. (3) High selectivity only reacts with the ortho-position C—H bonds in aromatic ketones and alkenes. If there are two different C—H bonds, the catalyst will only select one of the reactions. (4) Universality: This reaction has a very wide range of applications and is applicable to a variety of aromatic ketones and alkenes. (5) Easy to operate This catalytic reaction is very simple to operate, just mix and reflux.
This catalytic reaction is considered a remarkable achievement in the field of organic chemistry in recent decades [4,5]. Murai et al.’s research on ruthenium complex-catalyzed ortho-carbon-hydrogen bond cleavage of aromatic ketones and addition reactions with alkenes has just begun. It will play a great role in organic synthesis.
Physical and chemical properties and structure[1]
Triphenylphosphine hydrogenated carbonylruthenium(II) is also known as: carbonyl(dihydrogen)tris(triphenylphosphine)ruthenium(Ⅱ); carbonyl(dihydrogen)tris(triphenylphosphine)ruthenium; carbonyl Tris(triphenylphosphine)ruthenium(II) dihydrogen; tris(triphenylphosphine)ruthenium(II)carbonyldihydrogen; tris(triphenylphosphine)rutheniumcarbonyldihydrogen; tris(triphenylphosphine)carbonyldihydrogen Phosphine)ruthenium(II): IR18.6%MIN; carbonyl(dihydro)tris(triphenylphosphine)ruthenium. Molecular formula C55H45OP3Ru, a water-insoluble powder, has good catalytic performance for the addition reaction between the ortho position of the carbonyl group of aromatic ketones and alkene molecules.
Triphenylphosphine hydrogenated ruthenium(II)carbonyl
Apply[2]
1. Tris(triphenylphosphine)ruthenium(II)carbonyldihydrogen catalyzes the reaction of ferroceneethylene and substituted acetophenones to synthesize new ferrocene derivatives
The 25mL two-neck bottle is equipped with electromagnetic stirring and reflux condensation.�� and nitrogen conduit. After anhydrous and oxygen-free treatment, add 0.424g (2mmol) ferroceneethylene, 37mg (0.04mmol) tris(triphenylphosphine)carbonylruthenium(II), and 0.24mL (0.240g, 2mmol) benzene under nitrogen flow. ethanol and 3mL toluene. React in an oil bath at 135°C for 2 hours under nitrogen protection. The reaction solution was chromatographed on a neutral alumina column and eluted with petroleum ether-ethyl acetate (the volume ratio was 10:1) to obtain 0.450g of brown-red liquid (Ⅰ) with a yield of 68%. Elemental analysis (calculated values in parentheses, the same below): molecular formula C20H20OFe, C72.11% (72.31%), H6.10% (6.07%).
2.Synthesis of β-(2-acetyl-5-methoxyphenyl)ethylferrocene(Ⅱ)
Add 0.300g (2mmol) p-methoxyacetophenone, 37mg (0.04mmol) tris(triphenylphosphine)carbonylruthenium(II), and 0.424g (2mmol) ferrocene into a 25mL two-necked bottle. Ethylene and 3 mL of toluene. React in an oil bath at 135°C for 2 hours under nitrogen protection. The reaction solution was chromatographed on a neutral alumina column and eluted with petroleum ether-ethyl acetate (the volume ratio was 5:1) to obtain 0.580g of brown-red liquid (II) with a yield of 80%. Elemental analysis: Molecular formula C21H22O2Fe, C69.30% (69.63%), H6.17% (6.12%)
Preparation[2]
A 500mL four-neck flask is equipped with mechanical stirring, a reflux condenser connected to the nitrogen conduit at the top, and two balanced feeding tubes. After purging with nitrogen, add 3.14g (12mmol) triphenylphosphine and 140mL absolute ethanol to the flask and heat to vigorous boiling. Add 0.52g (2mmol) ruthenium trichloride in 20mL absolute ethanol solution, 22mL formaldehyde aqueous solution (mass fraction w=37%~40%) and 0.74gKOH (w≥82%) in 20mL absolute ethanol solution in sequence and quickly. into a vigorously stirred and refluxed ethanol solution of triphenylphosphine. Heat to reflux for 30 minutes.
Cool and filter to obtain gray precipitate. Wash with 40mLw=95% ethanol, 50mL deionized water, 40mL95% ethanol and 50mL petroleum ether in sequence, and obtain 1.28g of crude product after drying (literature yield 1.38g). Add 20 mL benzene to the crude product, heat to 50°C, and filter. Add 60 mL methanol to the filtrate to form a milky white turbid liquid. Leave to stand, precipitate out, filter with suction, and wash with 50 mL of methanol and 50 mL of petroleum ether to obtain a light gray solid. It was recrystallized again with benzene-methanol to obtain 0.89 g of white flaky solid.
Synthesis of β-(2-acetyl-5-chlorophenyl)ethylferrocene(Ⅲ):
Add 0.424g (2mmol) ferroceneethylene, 37mg (0.04mmol) carbonyldihydrogentri(triphenylphosphine)ruthenium, and 0.26mL (0.309g, 2mmol) p-chlorophenyl into a 25mL two-neck bottle. ketone and 3 mL of toluene. React in an oil bath at 135°C for 2 hours under nitrogen protection. The reaction solution was chromatographed on a neutral alumina column and eluted with petroleum ether-ethyl acetate (the volume ratio was 6:1) to obtain 0.360g of brown-red liquid (Ⅲ) with a yield of 49%
Main reference materials
[1]Du Hongguang, Wang Tao, Zhang Zhe, et al. Study on the reaction of ferroceneethylene and substituted acetophenones catalyzed by ruthenium monocarbonyl dihydrogen tri(triphenylphosphine)[J]. Journal of Beijing University of Chemical Technology , 1999, 26(4).
[2]Zhang Chunhui, Wang Bo, Wang Yanhui. Synthesis and characterization of ruthenium monocarbonyl dihydrogen tris(triphenylphosphine)[J]. Fine Petrochemicals, 2007, 24(3):1-3.
