A method for cross dehydrogenation coupling of aromatic carboxylic acid and α, β-unsaturated ester

A cross-dehydrogenation coupling, aromatic carboxylic acid technology, applied in the preparation of carboxylate, chemical instruments and methods, preparation of organic compounds and other directions, can solve the problems of harsh reaction conditions, many reaction steps, no reports, etc. The effect of mild reaction conditions, low temperature requirements and short reaction time

CN108191656BInactive Publication Date: 2021-02-02SHAANXI NORMAL UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2021-02-02
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method for cross dehydrogenation coupling of aromatic carboxylic acid and α, β-unsaturated ester. In the method, silver carbonate or silver fluoride is used as oxidant, and pentamethylcyclopentadienyl rhodium dichloride Dimer or bis(hexafluoroantimonate) triacetonitrile (pentamethylcyclopentadienyl) rhodium is used as a catalyst to catalyze the cross dehydrogenation coupling reaction of aromatic carboxylic acid and α, β-unsaturated ester. In the reaction, the ortho-position C-H bonds of aromatic carboxylic acids and α, β-unsaturated esters directly undergo cross-dehydrogenation coupling reactions, and a series of carboxyl-ortho-alkenylated aromatic carboxylic acid compounds are efficiently synthesized. The invention has the characteristics of simple and easy-to-obtain raw materials, mild reaction conditions, low reaction temperature, short time, simple operation and the like.
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Description

technical field

[0001] The present invention relates to the chemical reaction process of cross dehydrogenation coupling, in particular to a trivalent rhodium catalyzed cross dehydrogenation coupling reaction of aromatic carboxylic acid and α, β-unsaturated ester to prepare aromatic acid substituted by carboxyl ortho alkenyl . In the reaction, the ortho-position C-H bonds of aromatic carboxylic acids and α,β-unsaturated esters directly undergo cross-dehydrogenation coupling reactions. Background technique

[0002] As important organic intermediates, aryl olefins are widely used in biology, medicine, organic synthesis and other fields. The alkenylation reaction of aromatic hydrocarbons is an important method for preparing aryl olefins. The currently widely used alkenylation reaction is the Heck coupling reaction, that is, the coupling reaction between halogenated aromatic hydrocarbons and alkenes under the catalysis of transition metals. The Heck coupling reaction requires p...

Examples

Embodiment 1

[0018] Preparation of (E)-2-methyl-6-(3-benzyloxy-3-oxo-1-propenyl)benzoic acid with the following structural formula

[0019]

[0020] Add 13.6 mg (0.1 mmol) o-toluic acid, 30 μL (0.2 mmol) benzyl acrylate, and 3.1 mg (0.005 mmol) pentamethylcyclopentadienyl rhodium dichloride dimer to a 10 mL pressure-resistant reaction tube , 25.4mg (0.2mmol) of silver fluoride, 0.6mL of dioxane, stirred and reacted at 60°C for 3 hours under the protection of argon, cooled to room temperature after the reaction, and filtered through a column chromatography silica gel column (ethyl acetate lotion), remove the catalyst, and separate by thin layer chromatography (with petroleum ether, ethyl acetate, acetic acid volume ratio of 100:20:1 mixed solution as the developer), to obtain (E)-2-methyl-6- (3-benzyloxy-3-oxo-1-propenyl)benzoic acid, its yield is 64%, and the structural characterization data are as follows:

[0021] 1 H NMR (600MHz, CDCl 3 ):δ[ppm]=8.52(s,1H),8.00(d,J=15.8Hz,1H),7.47...

Embodiment 2

[0025] Preparation of (E)-2-ethyl-6-(3-benzyloxy-3-oxo-1-propenyl)benzoic acid with the following structural formula

[0026]

[0027] The o-toluic acid used in Example 1 is replaced with an equimolar amount of o-ethylbenzoic acid, and the other steps are the same as in Example 1 to obtain (E)-2-ethyl-6-(3-benzyloxy -3-oxo-1-propenyl)benzoic acid, its yield is 69%, and the structural characterization data are as follows:

[0028] 1 H NMR (400MHz, CDCl 3 ):δ[ppm]=9.47(s,1H),8.00(d,J=15.8Hz,1H),7.50(d,J=7.7Hz,1H),7.43-7.28(m,7H),6.48(d ,J=15.8Hz,1H),5.25(s,2H),2.78(q,J=7.5Hz,2H),1.27(t,J=7.5Hz,3H).

[0029] 13 C NMR (100MHz, CDCl 3 ): δ[ppm]=173.2, 166.6, 142.7, 142.2, 135.8, 133.0, 132.1, 130.6, 130.1, 128.5, 128.2, 128.1, 124.1, 120.3, 66.5, 26.9, 15.6.

[0030] HRMS(ESI)m / z:C 19 h 18 o 4 ,[M+Na] +, The theoretical value is 333.1103; the measured value is 333.1105.

Embodiment 3

[0032] Preparation of (E)-2-phenyl-6-(3-benzyloxy-3-oxo-1-propenyl)benzoic acid of the following structural formula

[0033]

[0034] The o-toluic acid used in Example 1 is replaced with 2-phenylbenzoic acid in equimolar amounts, and other steps are the same as in Example 1 to obtain (E)-2-phenyl-6-(3-benzyloxy Base-3-oxo-1-propenyl)benzoic acid, its yield is 65%, and the structural characterization data are as follows:

[0035] 1 H NMR (400MHz, CDCl 3 ):δ[ppm]=9.10(s,1H),8.02(d,J=15.8Hz,1H),7.64(d,J=7.7Hz,1H),7.49(t,J=7.8Hz,1H), 7.44-7.28(m,11H),6.52(d,J=15.8Hz,1H),5.24(s,2H).

[0036] 13 C NMR (150MHz, CDCl 3 ): δ[ppm]=172.9,166.4 142.2,140.9,139.8,135.8,133.1,132.4,131.6,129.9,128.5,128.4,128.3,128.2,128.2,127.8,125.3,121.0,66.5.

[0037] HRMS(ESI)m / z:C 23 h 18 o 4 ,[M+Na] + , The theoretical value is 381.1103; the measured value is 381.1101.