Samuele Rinaldi - Academia.edu (original) (raw)

Papers by Samuele Rinaldi

Research paper thumbnail of An efficient acid hydrolysis of the ether bond assisted by the neighbouring benzamide group. Part 3

Journal of the Chemical Society, Perkin Transactions 2, 2001

Research paper thumbnail of A simple asymmetric synthesis of (+)- and (−)-2,6-diaminopimelic acids

Tetrahedron: Asymmetry, 2000

The asymmetric synthesis of both the enantiomers of 2,6-diaminopimelic acid (2,6-DAP) has been ac... more The asymmetric synthesis of both the enantiomers of 2,6-diaminopimelic acid (2,6-DAP) has been accomplished starting from the chiral synthon 1. #

Research paper thumbnail of New isosteres of (R)-2-methylhomoserine and (R)-2-methylaspartic acid by alkylation of a chiral imine leading stereoselectively to a quaternary stereogenic center

Tetrahedron: Asymmetry, 2009

Imines obtained from either chiral 3-amino-4-silyloxymethylpyrrolidin-2-one 5a or 5b underwent al... more Imines obtained from either chiral 3-amino-4-silyloxymethylpyrrolidin-2-one 5a or 5b underwent alkylation to give, in good yield and total stereoselection, the corresponding 3,3,4-trisubstituted pyrrolidin-2-ones 8a–d where both the amino and the silyloxymethyl groups lie cis to each other, as shown by 1H NMR spectroscopic data and NOE experiments. By removal of both the imino group and the chiral inducer from 8b,

Research paper thumbnail of ChemInform Abstract: One-Pot Highly Stereoselective Reduction of β-Keto Amides to syn-γ-Aminols

Research paper thumbnail of Chiral 3-hydroxypyrrolidin-2-ones from a Baylis–Hillman adduct: convergent, stereoselective synthesis of a glycosidase inhibitor

Tetrahedron: Asymmetry, 2004

... doi:10.1016/j.tetasy.2004.08.016 | How to Cite or Link Using DOI Copyright © 2004 Elsevier Lt... more ... doi:10.1016/j.tetasy.2004.08.016 | How to Cite or Link Using DOI Copyright © 2004 Elsevier Ltd All rights reserved. Permissions & Reprints. Chiral 3-hydroxypyrrolidin-2-ones from aBaylis–Hillman adduct: convergent, stereoselective synthesis of a glycosidase inhibitor. ...

Research paper thumbnail of Synthesis of a conformationally restricted analog of pregabalin by stereoselective alkylation of a chiral pyrrolidin-2-one

Tetrahedron: Asymmetry, 2003

The 4-benzyloxymethyl pyrrolidin-2-one, 5, was alkylated leading to 3,4-trans-disubstituted pyrro... more The 4-benzyloxymethyl pyrrolidin-2-one, 5, was alkylated leading to 3,4-trans-disubstituted pyrrolidin-2-one 6 in good yield and total diastereoselection, as shown by 1 H NMR data and NOE experiments. After reduction of the carbonyl group to give the trans-3,4-disubstituted pyrrolidine 7, and removal of the chiral auxiliary, followed by protection of the nitrogen with t-Boc group, the corresponding N-protected pyrrolidine, 8 was obtained. The cleavage of the benzyl ether moiety, followed by oxidation of the hydroxy function, gave in good yield the corresponding pyrrolidine carboxylic acid 2, a restricted analog of pregabalin.

Research paper thumbnail of Chiral 3-hydroxypyrrolidin-2-ones. Part 2: Stereodivergent synthesis of conformationally restricted analogues of β-homoserine

Tetrahedron: Asymmetry, 2005

Starting from the homochiral 3-t-butyldimethylsilyloxypyrrolidin-2-one 2, a stereodivergent synth... more Starting from the homochiral 3-t-butyldimethylsilyloxypyrrolidin-2-one 2, a stereodivergent synthetic route was developed leading to both 3,4-trans- and 3,4-cis-3-amino-4-hydroxymethyl pyrrolidin-2-ones, 19 and 28, that are conformationally restricted analogues of β-homoserine 4. In addition, with a large number of 3,4-disubstituted pyrrolidin-2-ones in hand, a trend was observed for both H-3 chemical shifts and J3,4 values, allowing the configuration to be assigned to

Research paper thumbnail of Stereoselective synthesis of α,α′-diamino-dicarboxylic acids. Part 2

Tetrahedron: Asymmetry, 2000

Enantiomerically pure a,a%-diamino-dicarboxylic acids (R,R)-4, (S,S)-5 and (S,S)-7 have been synt... more Enantiomerically pure a,a%-diamino-dicarboxylic acids (R,R)-4, (S,S)-5 and (S,S)-7 have been synthesized starting from the glycine-derived chiral synthon (S,S)-1.

Research paper thumbnail of One-pot highly stereoselective reduction of β-keto amides to syn-γ-aminols

Tetrahedron Letters, 2001

In the presence of titanium tetrachloride, the borane/tetrahydrofuran complex can reduce 2-methyl... more In the presence of titanium tetrachloride, the borane/tetrahydrofuran complex can reduce 2-methyl-3-oxoamides into the corresponding syn-aminols in good yields and high diastereoselectivity. The use of borane/dimethyl sulfide instead of BH 3 /THF allows a partial reduction to syn-b-hydroxyamides.

Research paper thumbnail of Highly stereoselective titanium-mediated addition of organocerium reagents to β-keto amides: an efficient synthesis of stereodefined β-hydroxy amides having a tertiary alcoholic fragment

Tetrahedron Letters, 2001

A highly efficient and stereoselective protocol for the TiCl 4 -mediated addition of organocerium... more A highly efficient and stereoselective protocol for the TiCl 4 -mediated addition of organocerium reagents to b-keto amides is now available. The method allows the introduction of a large variety of carbon frameworks, including primary, secondary and tertiary alkyl chains, as well as aromatic, alkynylic and benzylic moieties, in high yields and with high stereoselection.

Research paper thumbnail of Acidity effect on the cleavage of ether function intramolecularly assisted by the amide group. Part 5

Tetrahedron, 2001

AbstractÐThe rate dependence on both the acidity and the temperature of the hydrolysis of N-(meth... more AbstractÐThe rate dependence on both the acidity and the temperature of the hydrolysis of N-(methoxyprop-2-yl)benzanilide (1), assisted by vicinal amide function, was investigated and the thermodynamic activation parameters were calculated. The rate constant of the ®rst step of the overall process increases when the acidity is raised, while the second step is slowed down. The negative value of DS ± (2100.9 J mol 21 K 21 ) measured for the second step suggests the participation of water in the transition state. q

Research paper thumbnail of Conformationally restricted analogues of both (S)-β-homoserine and (S)-aspartic acid from chiral 3-acylamino pyrrolidin-2-ones

Tetrahedron, 2005

Starting from chiral 3,4-trans-disubstituted pyrrolidin-2-ones 11a and 11b, obtained from a Bayli... more Starting from chiral 3,4-trans-disubstituted pyrrolidin-2-ones 11a and 11b, obtained from a Baylis-Hillman adduct, conformationally restricted analogues of both (S)-b-homoserine, 17, and (S)-aspartic acid, 21, were synthesized, respectively, and these compounds are suitable either for introduction in peptidomimetics or for synthesis of novel b-foldamers. q Entry d H-3 (ppm) d H-5 (ppm) d H-5 0 (ppm) J 3,4 (Hz) J 4,5 (Hz) J 4,5' (Hz)

Research paper thumbnail of Mechanistic investigation of an anomalous anchimeric assistance in the acid hydrolysis of the ether linkage. Part 4

Tetrahedron, 2001

AbstractÐKinetic investigation of the acid hydrolysis of N-(methoxyprop-2-yl)benzanilide (1) was ... more AbstractÐKinetic investigation of the acid hydrolysis of N-(methoxyprop-2-yl)benzanilide (1) was performed in 8.84 M HCl and/or DCl at 75.18C. The formation of 2-(N-phenylamino)propanol (4) was explained and the mechanism, involving an initial ether cleavage anchimerically assisted by the amide group, was clari®ed. The overall process evolves through three steps involving two intermediates. The rate constants of the individual processes have been determined by UV and 1 H NMR spectroscopic techniques. q

Research paper thumbnail of A novel conformationally restricted analogue of 3-methylaspartic acid via stereoselective methylation of chiral pyrrolidin-2-ones

Tetrahedron, 2010

Conformationally restricted analogues of β-methylaspartic acid were easily prepared starting from... more Conformationally restricted analogues of β-methylaspartic acid were easily prepared starting from chiral N-protected trans-3-amino-4-methoxycarbonyl pyrrolidin-2-ones. The key step of the synthesis was the methylation reaction at C-4, proceeding with high diastereoselection syn to the protected amino group lying at C-3 of the pyrrolidin-2-one ring.

Research paper thumbnail of Highly Diastereoselective Synthesis of β-Hydroxy Amides from β-Keto Amides

Synthesis, 2004

Carboxylic amides P 0320

Research paper thumbnail of α-Methylene-β-trichloroacetylamino Alkanoates from Trichloroacetimidates of the Baylis-Hillman Adducts

Synthesis, 2004

α-Methylene-β-trichloroacetylamino Alkanoates from Trichloroacetimidates of the Baylis-Hillman Ad... more α-Methylene-β-trichloroacetylamino Alkanoates from Trichloroacetimidates of the Baylis-Hillman Adducts. -Reaction of Baylis-Hillman adducts (I) with trichloroacetonitrile produces trichloracetimidates (III) which undergo thermal [3.3]sigmatropic rearrangement in refluxing toluene. On the other hand, in the presence of DABCO a rearrangement to trichloroacetamides (V) is observed. Products (IIIa) and (Va) undergo NIS-promoted iodocyclization. -(GALEAZZI, R.; MARTELLI, G.; ORENA*, M.; RINALDI, S.; Synthesis 2004, 15, 2560-2566; Dip. Sci. Mater. Terra, Univ. Ancona, I-60131 Ancona, Italy; Eng.) -Mais 11-097

Research paper thumbnail of Mg(ClO 4 ) 2 as a Powerful Catalyst for the Acylation of Alcohols under Solvent-Free Conditions

Synlett, 2002

Mg ClO 4 ) 2 as a Powerful Catalyst for the Acylation of Alcohols under Solvent--Free Conditions.... more Mg ClO 4 ) 2 as a Powerful Catalyst for the Acylation of Alcohols under Solvent--Free Conditions. -A trace amount of carefully dried anhydrous Mg(ClO 4 ) 2 is reported as efficient catalyst for the acylation of various alcohols. In the case of chiral substrates, no racemization or epimerization is observed. -(BARTOLI*, G.; BOSCO, M.; DALPOZZO, R.; MARCANTONI, E.; MASSACCESI, M.; RINALDI, S.; SAMBRI, L.; Synlett 2003, 1, 39-42; Dip. Chim. Org. "A. Mangini", Univ. Bologna, I-40136 Bologna, Italy; Eng.) -Mais 16-071

Research paper thumbnail of Stereoselective Iodocyclization of 3-Acylamino-2-methylene Alkanoates: Synthesis of Analogues of N -Benzoyl- s yn -phenylisoserine

Organic Letters, 2004

[reaction: see text] A convenient approach to racemic analogues of N-benzoyl-syn-phenylisoserine ... more [reaction: see text] A convenient approach to racemic analogues of N-benzoyl-syn-phenylisoserine was realized via the stereoselective iodocyclization of amides obtained from Baylis-Hillman adducts.

Research paper thumbnail of Straightforward Synthesis of (R,S)-β-Methyleneaspartic Acid, an Inhibitor of Glutamate-Aspartate Transaminase

Monatshefte für Chemie - Chemical Monthly, 2006

A Baylis-Hillman adduct of methyl acrylate and ethyl glyoxalate was converted into the trichloroa... more A Baylis-Hillman adduct of methyl acrylate and ethyl glyoxalate was converted into the trichloroacetimidate that in the presence of DABCO rearranged to the corresponding trichloroacetamide. Eventually, hydrolysis under acidic conditions, led to the hydrochloride of racemic -methyleneaspartic acid.

Research paper thumbnail of Stereodivergent Baylis-Hillman Reaction of a Chiral Acryloyl Imide Exploiting Ion-Chelation Effect: Mechanistic Insight on the Rearrangement of Trichloroacetimidates of the Baylis-Hillman Adducts to Trichloroacetamides

Monatshefte für Chemie - Chemical Monthly, 2007

In the presence of DABCO, ethyl glyoxalate and (4S,5R)-1,5-dimethyl-3-acryloyl-4-phenylimidazolid... more In the presence of DABCO, ethyl glyoxalate and (4S,5R)-1,5-dimethyl-3-acryloyl-4-phenylimidazolidin-2-one gave mixtures of the corresponding Baylis-Hillman adducts enriched in either isomer, depending on the absence or the presence of LiClO 4 in the reaction mixture. A diastereomeric mixture in 10:90 dr allowed to definitively establish the mechanism of the reaction leading to trichloroacetamides starting from trichloroacetimidates of the Baylis-Hillman adducts.

Research paper thumbnail of An efficient acid hydrolysis of the ether bond assisted by the neighbouring benzamide group. Part 3

Journal of the Chemical Society, Perkin Transactions 2, 2001

Research paper thumbnail of A simple asymmetric synthesis of (+)- and (−)-2,6-diaminopimelic acids

Tetrahedron: Asymmetry, 2000

The asymmetric synthesis of both the enantiomers of 2,6-diaminopimelic acid (2,6-DAP) has been ac... more The asymmetric synthesis of both the enantiomers of 2,6-diaminopimelic acid (2,6-DAP) has been accomplished starting from the chiral synthon 1. #

Research paper thumbnail of New isosteres of (R)-2-methylhomoserine and (R)-2-methylaspartic acid by alkylation of a chiral imine leading stereoselectively to a quaternary stereogenic center

Tetrahedron: Asymmetry, 2009

Imines obtained from either chiral 3-amino-4-silyloxymethylpyrrolidin-2-one 5a or 5b underwent al... more Imines obtained from either chiral 3-amino-4-silyloxymethylpyrrolidin-2-one 5a or 5b underwent alkylation to give, in good yield and total stereoselection, the corresponding 3,3,4-trisubstituted pyrrolidin-2-ones 8a–d where both the amino and the silyloxymethyl groups lie cis to each other, as shown by 1H NMR spectroscopic data and NOE experiments. By removal of both the imino group and the chiral inducer from 8b,

Research paper thumbnail of ChemInform Abstract: One-Pot Highly Stereoselective Reduction of β-Keto Amides to syn-γ-Aminols

Research paper thumbnail of Chiral 3-hydroxypyrrolidin-2-ones from a Baylis–Hillman adduct: convergent, stereoselective synthesis of a glycosidase inhibitor

Tetrahedron: Asymmetry, 2004

... doi:10.1016/j.tetasy.2004.08.016 | How to Cite or Link Using DOI Copyright © 2004 Elsevier Lt... more ... doi:10.1016/j.tetasy.2004.08.016 | How to Cite or Link Using DOI Copyright © 2004 Elsevier Ltd All rights reserved. Permissions & Reprints. Chiral 3-hydroxypyrrolidin-2-ones from aBaylis–Hillman adduct: convergent, stereoselective synthesis of a glycosidase inhibitor. ...

Research paper thumbnail of Synthesis of a conformationally restricted analog of pregabalin by stereoselective alkylation of a chiral pyrrolidin-2-one

Tetrahedron: Asymmetry, 2003

The 4-benzyloxymethyl pyrrolidin-2-one, 5, was alkylated leading to 3,4-trans-disubstituted pyrro... more The 4-benzyloxymethyl pyrrolidin-2-one, 5, was alkylated leading to 3,4-trans-disubstituted pyrrolidin-2-one 6 in good yield and total diastereoselection, as shown by 1 H NMR data and NOE experiments. After reduction of the carbonyl group to give the trans-3,4-disubstituted pyrrolidine 7, and removal of the chiral auxiliary, followed by protection of the nitrogen with t-Boc group, the corresponding N-protected pyrrolidine, 8 was obtained. The cleavage of the benzyl ether moiety, followed by oxidation of the hydroxy function, gave in good yield the corresponding pyrrolidine carboxylic acid 2, a restricted analog of pregabalin.

Research paper thumbnail of Chiral 3-hydroxypyrrolidin-2-ones. Part 2: Stereodivergent synthesis of conformationally restricted analogues of β-homoserine

Tetrahedron: Asymmetry, 2005

Starting from the homochiral 3-t-butyldimethylsilyloxypyrrolidin-2-one 2, a stereodivergent synth... more Starting from the homochiral 3-t-butyldimethylsilyloxypyrrolidin-2-one 2, a stereodivergent synthetic route was developed leading to both 3,4-trans- and 3,4-cis-3-amino-4-hydroxymethyl pyrrolidin-2-ones, 19 and 28, that are conformationally restricted analogues of β-homoserine 4. In addition, with a large number of 3,4-disubstituted pyrrolidin-2-ones in hand, a trend was observed for both H-3 chemical shifts and J3,4 values, allowing the configuration to be assigned to

Research paper thumbnail of Stereoselective synthesis of α,α′-diamino-dicarboxylic acids. Part 2

Tetrahedron: Asymmetry, 2000

Enantiomerically pure a,a%-diamino-dicarboxylic acids (R,R)-4, (S,S)-5 and (S,S)-7 have been synt... more Enantiomerically pure a,a%-diamino-dicarboxylic acids (R,R)-4, (S,S)-5 and (S,S)-7 have been synthesized starting from the glycine-derived chiral synthon (S,S)-1.

Research paper thumbnail of One-pot highly stereoselective reduction of β-keto amides to syn-γ-aminols

Tetrahedron Letters, 2001

In the presence of titanium tetrachloride, the borane/tetrahydrofuran complex can reduce 2-methyl... more In the presence of titanium tetrachloride, the borane/tetrahydrofuran complex can reduce 2-methyl-3-oxoamides into the corresponding syn-aminols in good yields and high diastereoselectivity. The use of borane/dimethyl sulfide instead of BH 3 /THF allows a partial reduction to syn-b-hydroxyamides.

Research paper thumbnail of Highly stereoselective titanium-mediated addition of organocerium reagents to β-keto amides: an efficient synthesis of stereodefined β-hydroxy amides having a tertiary alcoholic fragment

Tetrahedron Letters, 2001

A highly efficient and stereoselective protocol for the TiCl 4 -mediated addition of organocerium... more A highly efficient and stereoselective protocol for the TiCl 4 -mediated addition of organocerium reagents to b-keto amides is now available. The method allows the introduction of a large variety of carbon frameworks, including primary, secondary and tertiary alkyl chains, as well as aromatic, alkynylic and benzylic moieties, in high yields and with high stereoselection.

Research paper thumbnail of Acidity effect on the cleavage of ether function intramolecularly assisted by the amide group. Part 5

Tetrahedron, 2001

AbstractÐThe rate dependence on both the acidity and the temperature of the hydrolysis of N-(meth... more AbstractÐThe rate dependence on both the acidity and the temperature of the hydrolysis of N-(methoxyprop-2-yl)benzanilide (1), assisted by vicinal amide function, was investigated and the thermodynamic activation parameters were calculated. The rate constant of the ®rst step of the overall process increases when the acidity is raised, while the second step is slowed down. The negative value of DS ± (2100.9 J mol 21 K 21 ) measured for the second step suggests the participation of water in the transition state. q

Research paper thumbnail of Conformationally restricted analogues of both (S)-β-homoserine and (S)-aspartic acid from chiral 3-acylamino pyrrolidin-2-ones

Tetrahedron, 2005

Starting from chiral 3,4-trans-disubstituted pyrrolidin-2-ones 11a and 11b, obtained from a Bayli... more Starting from chiral 3,4-trans-disubstituted pyrrolidin-2-ones 11a and 11b, obtained from a Baylis-Hillman adduct, conformationally restricted analogues of both (S)-b-homoserine, 17, and (S)-aspartic acid, 21, were synthesized, respectively, and these compounds are suitable either for introduction in peptidomimetics or for synthesis of novel b-foldamers. q Entry d H-3 (ppm) d H-5 (ppm) d H-5 0 (ppm) J 3,4 (Hz) J 4,5 (Hz) J 4,5' (Hz)

Research paper thumbnail of Mechanistic investigation of an anomalous anchimeric assistance in the acid hydrolysis of the ether linkage. Part 4

Tetrahedron, 2001

AbstractÐKinetic investigation of the acid hydrolysis of N-(methoxyprop-2-yl)benzanilide (1) was ... more AbstractÐKinetic investigation of the acid hydrolysis of N-(methoxyprop-2-yl)benzanilide (1) was performed in 8.84 M HCl and/or DCl at 75.18C. The formation of 2-(N-phenylamino)propanol (4) was explained and the mechanism, involving an initial ether cleavage anchimerically assisted by the amide group, was clari®ed. The overall process evolves through three steps involving two intermediates. The rate constants of the individual processes have been determined by UV and 1 H NMR spectroscopic techniques. q

Research paper thumbnail of A novel conformationally restricted analogue of 3-methylaspartic acid via stereoselective methylation of chiral pyrrolidin-2-ones

Tetrahedron, 2010

Conformationally restricted analogues of β-methylaspartic acid were easily prepared starting from... more Conformationally restricted analogues of β-methylaspartic acid were easily prepared starting from chiral N-protected trans-3-amino-4-methoxycarbonyl pyrrolidin-2-ones. The key step of the synthesis was the methylation reaction at C-4, proceeding with high diastereoselection syn to the protected amino group lying at C-3 of the pyrrolidin-2-one ring.

Research paper thumbnail of Highly Diastereoselective Synthesis of β-Hydroxy Amides from β-Keto Amides

Synthesis, 2004

Carboxylic amides P 0320

Research paper thumbnail of α-Methylene-β-trichloroacetylamino Alkanoates from Trichloroacetimidates of the Baylis-Hillman Adducts

Synthesis, 2004

α-Methylene-β-trichloroacetylamino Alkanoates from Trichloroacetimidates of the Baylis-Hillman Ad... more α-Methylene-β-trichloroacetylamino Alkanoates from Trichloroacetimidates of the Baylis-Hillman Adducts. -Reaction of Baylis-Hillman adducts (I) with trichloroacetonitrile produces trichloracetimidates (III) which undergo thermal [3.3]sigmatropic rearrangement in refluxing toluene. On the other hand, in the presence of DABCO a rearrangement to trichloroacetamides (V) is observed. Products (IIIa) and (Va) undergo NIS-promoted iodocyclization. -(GALEAZZI, R.; MARTELLI, G.; ORENA*, M.; RINALDI, S.; Synthesis 2004, 15, 2560-2566; Dip. Sci. Mater. Terra, Univ. Ancona, I-60131 Ancona, Italy; Eng.) -Mais 11-097

Research paper thumbnail of Mg(ClO 4 ) 2 as a Powerful Catalyst for the Acylation of Alcohols under Solvent-Free Conditions

Synlett, 2002

Mg ClO 4 ) 2 as a Powerful Catalyst for the Acylation of Alcohols under Solvent--Free Conditions.... more Mg ClO 4 ) 2 as a Powerful Catalyst for the Acylation of Alcohols under Solvent--Free Conditions. -A trace amount of carefully dried anhydrous Mg(ClO 4 ) 2 is reported as efficient catalyst for the acylation of various alcohols. In the case of chiral substrates, no racemization or epimerization is observed. -(BARTOLI*, G.; BOSCO, M.; DALPOZZO, R.; MARCANTONI, E.; MASSACCESI, M.; RINALDI, S.; SAMBRI, L.; Synlett 2003, 1, 39-42; Dip. Chim. Org. "A. Mangini", Univ. Bologna, I-40136 Bologna, Italy; Eng.) -Mais 16-071

Research paper thumbnail of Stereoselective Iodocyclization of 3-Acylamino-2-methylene Alkanoates: Synthesis of Analogues of N -Benzoyl- s yn -phenylisoserine

Organic Letters, 2004

[reaction: see text] A convenient approach to racemic analogues of N-benzoyl-syn-phenylisoserine ... more [reaction: see text] A convenient approach to racemic analogues of N-benzoyl-syn-phenylisoserine was realized via the stereoselective iodocyclization of amides obtained from Baylis-Hillman adducts.

Research paper thumbnail of Straightforward Synthesis of (R,S)-β-Methyleneaspartic Acid, an Inhibitor of Glutamate-Aspartate Transaminase

Monatshefte für Chemie - Chemical Monthly, 2006

A Baylis-Hillman adduct of methyl acrylate and ethyl glyoxalate was converted into the trichloroa... more A Baylis-Hillman adduct of methyl acrylate and ethyl glyoxalate was converted into the trichloroacetimidate that in the presence of DABCO rearranged to the corresponding trichloroacetamide. Eventually, hydrolysis under acidic conditions, led to the hydrochloride of racemic -methyleneaspartic acid.

Research paper thumbnail of Stereodivergent Baylis-Hillman Reaction of a Chiral Acryloyl Imide Exploiting Ion-Chelation Effect: Mechanistic Insight on the Rearrangement of Trichloroacetimidates of the Baylis-Hillman Adducts to Trichloroacetamides

Monatshefte für Chemie - Chemical Monthly, 2007

In the presence of DABCO, ethyl glyoxalate and (4S,5R)-1,5-dimethyl-3-acryloyl-4-phenylimidazolid... more In the presence of DABCO, ethyl glyoxalate and (4S,5R)-1,5-dimethyl-3-acryloyl-4-phenylimidazolidin-2-one gave mixtures of the corresponding Baylis-Hillman adducts enriched in either isomer, depending on the absence or the presence of LiClO 4 in the reaction mixture. A diastereomeric mixture in 10:90 dr allowed to definitively establish the mechanism of the reaction leading to trichloroacetamides starting from trichloroacetimidates of the Baylis-Hillman adducts.