- New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions
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The preparation of new organocatalysts for asymmetric syntheses has become a key stage of enantioselective catalysis. In particular, the development of new cyclodextrin (CD)-based organocatalysts allowed to perform enantioselective reactions in water and
- Tichá, Iveta Chena,Hybelbauerová, Simona,Jind?ich, Jind?ich
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Read Online
- Method for preparing spiro beta-lactam
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The invention discloses a method for preparing spiro beta-lactam. The method comprises the following step: carrying out [2+1] cyclization reaction on beta-lactam and keto ester under the condition ofa phosphine catalyst to generate spiro beta-lactam. The
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Paragraph 0052-0054; 0057
(2020/07/12)
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- Highly Regio- and Enantioselective Alkoxycarbonylative Amination of Terminal Allenes Catalyzed by a Spiroketal-Based Diphosphine/Pd(II) Complex
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An enantioselective alkoxycarbonylation-amination cascade process of terminal allenes with CO, methanol, and arylamines has been developed. It proceeds under mild conditions (room temperature, ambient pressure CO) via oxidative Pd(II) catalysis using an aromatic spiroketal-based diphosphine (SKP) as a chiral ligand and a Cu(II) salt as an oxidant and affords a wide range of α-methylene-β-arylamino acid esters (36 examples) in good yields with excellent enantioselectivity (up to 96% ee) and high regioselectivity (branched/linear > 92:8). Preliminary mechanistic studies suggested that the reaction is likely to proceed through alkoxycarbonylpalladation of the allene followed by an amination process. The synthetic utility of the protocol is showcased in the asymmetric construction of a cycloheptene-fused chiral β-lactam.
- Liu, Jiawang,Han, Zhaobin,Wang, Xiaoming,Wang, Zheng,Ding, Kuiling
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p. 15346 - 15349
(2015/12/26)
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- A simple and direct synthesis of 3-methylene-1, 4-diarylazetidin-2-ones and (E)-3-arylidene-1-phenylazetidin-2-ones using baylis-hillman derivatives
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Herein we describe a direct method, promoted by potassium tert-butoxide (KOtBu), for the synthesis of highly substituted α-methylene β-lactams and α-arylidene β-lactams from the amino ester intermediates derived from the acetates and bromo derivatives of
- Bakthadoss, Manickam,Srinivasan, Jayakumar,Selvakumar, Raman
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p. 295 - 301
(2014/03/21)
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- Palladium-catalyzed α-regioselective allylic amination of Morita-Baylis-Hillman acetates with simple aromatic amines
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An efficient allylic amination of Morita-Baylis-Hillman acetates with simple aromatic amines provided good yields with excellent α- regioselectivity (up to exclusive α-product) under the catalysis of Pd2(dba)3/ferrocene-type diphosph
- Wang, Yan,Liu, Li,Wang, Dong,Chen, Yong-Jun
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p. 6908 - 6913
(2012/11/07)
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- Accelerated amination of baylis-hillman acetates under ultrasound irradiation
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The amination of the Baylis-Hillman acetates with primary amines can be dramatically promoted with improved yields and shortened reaction time under ultrasound irradiation. The selected aromatic, heteroaromatic, and aliphatic amines were investigated as t
- Ge, Shao-Qin,Hua, Yun-Yu,Xia, Min
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experimental part
p. 1954 - 1962
(2010/09/09)
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- Synthesis of β-amino esters by regioselective amination of allyl bromides with aryl and alkyl amines
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One of the two possible regioisomers can be exclusively formed by combining a suitable solvent and a specific amount of triethylamine as a base during the amination of allyl bromide 5. The SN2′ product 7 was produced using dichloromethane as a
- Chen, Hung-Yang,Patkar, Laxmikant N.,Ueng, Shau-Hua,Lin, Chun-Cheng,Lee, Adam Shih-Yuan
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p. 2035 - 2038
(2007/10/03)
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- Chemical transformation of Baylis-Hillman adducts: The reaction of methyl 3-arylamino-2-methylene-3-phenylpropanoates in polyphosphoric acid
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We synthesized some interesting compounds including 3-benzylidene-3,4- dihydro-1H-quinolin-2-one, 3-benzylquinolin-2-ol, 4-amino-2-benzylideneindan-1- one, and 1-amino-9a,10-dihydro-4bH-indeno[1,2-a]inden-9-one skeletons starting from Baylis-Hillman adducts.
- Lee, Chang Gon,Lee, Ka Young,Lee, Sangku,Kim, Jae Nyoung
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p. 1493 - 1499
(2007/10/03)
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- Palladium(0)-catalyzed regioselective synthesis of α-dehydro-β-amino esters from amines and allyl acetates: Synthesis of a α-dehydro-β-amino acid derived cyclic peptide as a constrained β-turn mimic
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Acetates derived from the adducts of the Baylis-Hillman reaction can be reacted in a regioselective manner with amines in the presence of palladium(0) catalyst to afford α-dehydro-β-amino esters (2 and 3) in good yields. The regioselectivity of the reaction can be controlled by temperature and reaction medium leading to the synthesis of regioisomers 2 or 3. The α-dehydro-β-amino acid 3 is a turn inducer, and the dipeptides 6 derived from it show the presence of an eight-membered intramolecular hydrogen bond. Also, cobalt(II) chloride catalyzes the cleavage of epoxy peptides with α-dehydro-β-amino acid derivative 3b to afford the corresponding dipeptide derivatives 8, which exhibit an intramolecular hydrogen bond and thus mimic a β-turn. This intramolecular hydrogen bonding preorganizes the corresponding diallylated peptide 8c for cyclization via ring-closing metathesis to afford the cyclic peptide 9 as a constrained mimic of a β-turn.
- Rajesh,Banerji, Biswadip,Iqbal, Javed
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p. 7852 - 7857
(2007/10/03)
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- 115. α-Methylidene-and α-alkylidene-β-lactams from nonproteinogenic amino acids
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Treatment of methyl 2-(l-hydroxyalkyl)prop-2-enoates1 with conc. HBr solution afforded methyl (Z)-2-(bromomethyl)alk-2-enoates 2, which were transformed regioselectively into N-substituted methyl (E)-2-(aminomethyl)alk-2-enoates 3 (SN2 reaction
- Buchholz, Rainer,Hoffmann, H. Martin R.
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p. 1213 - 1220
(2015/01/08)
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