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Catalysis
Catalysis Patent: Assignee: Utility:
Highly Reactive Form of Copper and Reagents Thereof R.D. Rieke, US Patent 5,490,952 (February 13, 1996) University of Nebraska Organo Copper Reagents
Reaction 0
+ Li
• Note 1
CuCN.2LiBr
-^^-^ Note 2
Cu-
-^U^
OEt Not Isolated 0
-' 0 OEt
^ i- THF, lithium bromide, copper(I)cyanide ii- Ethyl 4-bromobutyrate, benzoyl chloride
Experimental 1. Copper(I)cyanide di(lithium bromide) Lithium (8.46 mmol) and naphthalene (10.1 mmol) were mixed with 15 ml THF, stirred 2 hours, and then cooled to -100°C. In a separate reaction vessel, CuCN (8.0 mmol) and LiBr (17.27 mmol) in 5 ml THF were stirred until the Cu(I) salt dissolved. The solution was cooled to —40°C and transferred into lithium naphthalide using a cannula and the mixture stirred 5 minutes. The catalytic agent was ready for immediate use.
206
ADVANCES IN SYNTHETIC ORGANIC CHEMISTRY
2. Ethyl 4-ketophenylbutyrate The product from Step 1 was warmed to — 35°C, charged with ethyl 4-bromobutyrate (1.95 mol), stirred 10 minutes, and benzoyl chloride (3 equiv.) added via syringe at —35°C. The solution was stirred 30 minutes, quenched with NH4CI, and the product isolated by flash chromatography techniques.
Derivatives Halide
Electrophile
Yield (%)
Product
O CI
CI
67 O^^CI
87 O^^CI Br ^
o 82
Notes 1. A second method for preparing the Step 1 zerovalent copper reagent was also provided by the author and described below: Procedure Lithium metal (8.40 mmol) and naphthalene (9.20 mmol) were mixed in 10 ml THF at ambient temperature 2 hours and then cooled to — 108°C. Lithium 2-thienylcyanocuprate (32ml 0.25 M) was added via cannula at -50°C and the solution stirred at -108°C 30 minutes. The resulting zerovalent copper species was ready for immediate use. 2. Other methods for preparing zerovalent copper of the current invention are provided (1,2,3).
207
CATALYSIS
3. Bisorganocopper reagents were also prepared by the author using 2,3-ciichloropentene and subsequently reacted with two electrophiles as illustrated in Eq. 1: CI
Eq-l
Cu
E2
Cu
J ^ CI
Derivatives El
^^-^
PhCHO
Yield r/o)
Product
El
Br
71
69
PhCHO
I
OH ON
^^
^ ^ ^ '
>
32
54
OH CN
References 1. EJ. Corey etal. Tetrahedron Lett., 26, 6015, (1985); ibid., 26, 6019 (1985); A. Alexakis etal, ibid., 27, 1047 (1986) 2. W.J. Bartlet etal US Patent 4,687,877 (August 18, 1987) 3. M.S.Cohen etal US Patent 4,152,303 (May 1, 1979)
ADVANCES IN SYNTHETIC ORGANIC CHEMISTRY
208
Patent:
Lewis Acid Catalyst Composition J. Nishlkido etaU US Patent 6,436,866 (August 20, 2002) Asahi Kasei Kabushiki Kaisha Lanthanide Lewis Acid Catalysts
Assignee: Utility: Reaction
MesSiO \
OMe
/
r0SiMe3
OMe
Note 1
i- Ytterbium tris(tris(perfluorooctanesulfonyl)methide), toluene, perfluorooctane, toluene
Experimental 1. Methyl 3-trimethylsiloxy-2,2-dimethyl-3-phenylpropionate Benzaldehyde (81 mg) and methyl trimethoxysilyl dimethylketene acetal (165 mg) were added to a mixure of 3 ml perfluorooctane and 4 ml toluene. To this mixture was added Imol % (based on benzaldehyde) ytterbium (tris(trisperfluorooctanesulfonyl)methide) and the reaction stirred 15 minutes at 40°C. Mixing and heating were stopped and the mixture separated into upper toluene layer and lower perfluorooctane layer. Each layer was analyzed by gas chromatography; 99% of the product was detected in the lower layer. Atomic emission spectrometry indicated that at least 99% of the catalyst was also present in the lower layer.
Catalyst Preparation 1. Preparation of ytterbium tris(tris(perfluorobutanesulfonyl)-methide) Tris(perfluorobutanesulfonyl)methide (3.0 g) was added to a solution of 15 ml acetonitrile, 15 ml water, and ytterbium carbonate (0.39 g). The mixture was stirred 7 hours at ambient temperature and was then heated to 50 °C one hour. The mixture was filtered and the product isolated by vacuum drying at 50°C at 1-10 mm Hg followed by drying at 90°C at 0.01 mm Hg for 24 hours. Elemental analysis supphed. 2. Preparation of scandium tris(tris(perfluorooctanesulfonyl)methide) Tris(perfluorooctanesulfonyl)methide (5.0 g) was added to a solution containing 10 ml acetonitrile, 10 ml water, and scandium acetate (0.25 g). The mixture stirred 5 hours at ambient temperature and then heated to 50 °C one hour. The product was isolated as in the aforestated method. Elemental analysis supplied.
CATALYSIS
209
Catalyst Summary 1. Preferred combinations of Lewis acid catalyst and perfluoro co-solvent are listed below: Cation (III) Ytterbium
Counterion Perfluorobutanesulfonylmethide,
Lanthanum
Perfluorooctylsulfonylimide, (C8F,5S02)2N Perflurorbutylsulfonylmethide, (C4F9S02)3C
Perfluoro Solvent Perfluorooctane, CgFjg
(C4F5S02)3C
Scandium
Perfluorocyclohexane, C6F12
Perfluorotoluene C6F5CF3
Catalyzed Reactions 1. Catalytic effectiveness was assessed using the reaction of anisole and acetic anhydride forming 4-methoxyacetophenone in chlorobenzene and are summarized below: Catalyst None AICI3 ((C4F9S02)3C)3Yb ((C4F9S02)3C)3La ((C8Fi,S02)3C)3Sc
Yield (%) 0.1 4.0 80 83 78
3. The effectiveness of the Lewis acid catalysts in electrophilic substitution, esterification, Diels-Adler cyclization, and lactonization reactions, respectively, is summarized below: Reaction Type Electrophilic
Reagent 1
Reagent 2
Catalyst
Product
Anisole
Acetic anhydride
((C4F9S02)2N)3Yt
Esterification Diels-Adler
Cyclohexanol 2,3-Dimethylbutadiene 2-Adamanta-none
Acetic anhydride Methyl vinyl ketone Hydrogen Peroxide
4-Methoxyacetophenone Cyclohexyl-acetate 4-Acetyl-1,2-dimethylcyclohexene Baeyer-Villiger lactone
Lactonization
Yield
(%) (C4F9S03)3Yb ((C4F9S02)2N)3La ((C8Fi7S02)2N)3Sc
97 98 86 61
Notes These Lewis acids require a two solvent medium for optimum utility. The perfluoro aliphatic component constitutes the first which dissolves the catalyst (1). The second component is preferably consists of a halocarbon such as dichloro- and dibromomethane; mono- and dichlorobenzene; chlorotoluene; and bromobenzene. Toluene has also been found to be effective. Interfacial agents have also been used and are discussed (2).
210
ADVANCES IN SYNTHETIC ORGANIC CHEMISTRY
2. Gallium perfluoroalkanesulfonates Lewis acid catalysts have also been prepared and used in isomerization of branched-chain alkanes (3,4). 3. Lanthanum derivatives containing either bis(2-ethylhexyl)phosphate or 4-nonylphenoxide ligands have been found effetive in polymerizing trans-butadiene (5).
References 1. 2. 3. 4. 5.
I. Prakash, US Patent 6,642,406 (November 4, 2003) I.T. Horvath etal, US Patent 5,463,082 (October 31, 1995) G.A. Olah, US Patent 5,110,778 (May 5, 1992) G.A. Olah, US Patent 4,721,559 (January 26, 1988) T.J. Lynch, US Patent 6,184,168 (February 6, 2001)
Highly Reactive Form of Copper and Reagents Thereof R.D. Rieke, US Patent 5,490,952 (February 13, 1996) University of Nebraska Organo Copper Reagents
Reaction 0
+ Li
• Note 1
CuCN.2LiBr
-^^-^ Note 2
Cu-
-^U^
OEt Not Isolated 0
-' 0 OEt
^ i- THF, lithium bromide, copper(I)cyanide ii- Ethyl 4-bromobutyrate, benzoyl chloride
Experimental 1. Copper(I)cyanide di(lithium bromide) Lithium (8.46 mmol) and naphthalene (10.1 mmol) were mixed with 15 ml THF, stirred 2 hours, and then cooled to -100°C. In a separate reaction vessel, CuCN (8.0 mmol) and LiBr (17.27 mmol) in 5 ml THF were stirred until the Cu(I) salt dissolved. The solution was cooled to —40°C and transferred into lithium naphthalide using a cannula and the mixture stirred 5 minutes. The catalytic agent was ready for immediate use.
206
ADVANCES IN SYNTHETIC ORGANIC CHEMISTRY
2. Ethyl 4-ketophenylbutyrate The product from Step 1 was warmed to — 35°C, charged with ethyl 4-bromobutyrate (1.95 mol), stirred 10 minutes, and benzoyl chloride (3 equiv.) added via syringe at —35°C. The solution was stirred 30 minutes, quenched with NH4CI, and the product isolated by flash chromatography techniques.
Derivatives Halide
Electrophile
Yield (%)
Product
O CI
CI
67 O^^CI
87 O^^CI Br ^
o 82
Notes 1. A second method for preparing the Step 1 zerovalent copper reagent was also provided by the author and described below: Procedure Lithium metal (8.40 mmol) and naphthalene (9.20 mmol) were mixed in 10 ml THF at ambient temperature 2 hours and then cooled to — 108°C. Lithium 2-thienylcyanocuprate (32ml 0.25 M) was added via cannula at -50°C and the solution stirred at -108°C 30 minutes. The resulting zerovalent copper species was ready for immediate use. 2. Other methods for preparing zerovalent copper of the current invention are provided (1,2,3).
207
CATALYSIS
3. Bisorganocopper reagents were also prepared by the author using 2,3-ciichloropentene and subsequently reacted with two electrophiles as illustrated in Eq. 1: CI
Eq-l
Cu
E2
Cu
J ^ CI
Derivatives El
^^-^
PhCHO
Yield r/o)
Product
El
Br
71
69
PhCHO
I
OH ON
^^
^ ^ ^ '
>
32
54
OH CN
References 1. EJ. Corey etal. Tetrahedron Lett., 26, 6015, (1985); ibid., 26, 6019 (1985); A. Alexakis etal, ibid., 27, 1047 (1986) 2. W.J. Bartlet etal US Patent 4,687,877 (August 18, 1987) 3. M.S.Cohen etal US Patent 4,152,303 (May 1, 1979)
ADVANCES IN SYNTHETIC ORGANIC CHEMISTRY
208
Patent:
Lewis Acid Catalyst Composition J. Nishlkido etaU US Patent 6,436,866 (August 20, 2002) Asahi Kasei Kabushiki Kaisha Lanthanide Lewis Acid Catalysts
Assignee: Utility: Reaction
MesSiO \
OMe
/
r0SiMe3
OMe
Note 1
i- Ytterbium tris(tris(perfluorooctanesulfonyl)methide), toluene, perfluorooctane, toluene
Experimental 1. Methyl 3-trimethylsiloxy-2,2-dimethyl-3-phenylpropionate Benzaldehyde (81 mg) and methyl trimethoxysilyl dimethylketene acetal (165 mg) were added to a mixure of 3 ml perfluorooctane and 4 ml toluene. To this mixture was added Imol % (based on benzaldehyde) ytterbium (tris(trisperfluorooctanesulfonyl)methide) and the reaction stirred 15 minutes at 40°C. Mixing and heating were stopped and the mixture separated into upper toluene layer and lower perfluorooctane layer. Each layer was analyzed by gas chromatography; 99% of the product was detected in the lower layer. Atomic emission spectrometry indicated that at least 99% of the catalyst was also present in the lower layer.
Catalyst Preparation 1. Preparation of ytterbium tris(tris(perfluorobutanesulfonyl)-methide) Tris(perfluorobutanesulfonyl)methide (3.0 g) was added to a solution of 15 ml acetonitrile, 15 ml water, and ytterbium carbonate (0.39 g). The mixture was stirred 7 hours at ambient temperature and was then heated to 50 °C one hour. The mixture was filtered and the product isolated by vacuum drying at 50°C at 1-10 mm Hg followed by drying at 90°C at 0.01 mm Hg for 24 hours. Elemental analysis supphed. 2. Preparation of scandium tris(tris(perfluorooctanesulfonyl)methide) Tris(perfluorooctanesulfonyl)methide (5.0 g) was added to a solution containing 10 ml acetonitrile, 10 ml water, and scandium acetate (0.25 g). The mixture stirred 5 hours at ambient temperature and then heated to 50 °C one hour. The product was isolated as in the aforestated method. Elemental analysis supplied.
CATALYSIS
209
Catalyst Summary 1. Preferred combinations of Lewis acid catalyst and perfluoro co-solvent are listed below: Cation (III) Ytterbium
Counterion Perfluorobutanesulfonylmethide,
Lanthanum
Perfluorooctylsulfonylimide, (C8F,5S02)2N Perflurorbutylsulfonylmethide, (C4F9S02)3C
Perfluoro Solvent Perfluorooctane, CgFjg
(C4F5S02)3C
Scandium
Perfluorocyclohexane, C6F12
Perfluorotoluene C6F5CF3
Catalyzed Reactions 1. Catalytic effectiveness was assessed using the reaction of anisole and acetic anhydride forming 4-methoxyacetophenone in chlorobenzene and are summarized below: Catalyst None AICI3 ((C4F9S02)3C)3Yb ((C4F9S02)3C)3La ((C8Fi,S02)3C)3Sc
Yield (%) 0.1 4.0 80 83 78
3. The effectiveness of the Lewis acid catalysts in electrophilic substitution, esterification, Diels-Adler cyclization, and lactonization reactions, respectively, is summarized below: Reaction Type Electrophilic
Reagent 1
Reagent 2
Catalyst
Product
Anisole
Acetic anhydride
((C4F9S02)2N)3Yt
Esterification Diels-Adler
Cyclohexanol 2,3-Dimethylbutadiene 2-Adamanta-none
Acetic anhydride Methyl vinyl ketone Hydrogen Peroxide
4-Methoxyacetophenone Cyclohexyl-acetate 4-Acetyl-1,2-dimethylcyclohexene Baeyer-Villiger lactone
Lactonization
Yield
(%) (C4F9S03)3Yb ((C4F9S02)2N)3La ((C8Fi7S02)2N)3Sc
97 98 86 61
Notes These Lewis acids require a two solvent medium for optimum utility. The perfluoro aliphatic component constitutes the first which dissolves the catalyst (1). The second component is preferably consists of a halocarbon such as dichloro- and dibromomethane; mono- and dichlorobenzene; chlorotoluene; and bromobenzene. Toluene has also been found to be effective. Interfacial agents have also been used and are discussed (2).
210
ADVANCES IN SYNTHETIC ORGANIC CHEMISTRY
2. Gallium perfluoroalkanesulfonates Lewis acid catalysts have also been prepared and used in isomerization of branched-chain alkanes (3,4). 3. Lanthanum derivatives containing either bis(2-ethylhexyl)phosphate or 4-nonylphenoxide ligands have been found effetive in polymerizing trans-butadiene (5).
References 1. 2. 3. 4. 5.
I. Prakash, US Patent 6,642,406 (November 4, 2003) I.T. Horvath etal, US Patent 5,463,082 (October 31, 1995) G.A. Olah, US Patent 5,110,778 (May 5, 1992) G.A. Olah, US Patent 4,721,559 (January 26, 1988) T.J. Lynch, US Patent 6,184,168 (February 6, 2001)