- Synthesis of 2-Hydroxy-1-naphthoic Acid Derivatives by Oxidative Cyclization of Esters of 5-Aryl-3-oxopentanoic Acid by Mn(III) and Ce(IV) Salts
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A new synthesis of substituted 2-hydroxy-1-naphthoic acid esters and amides 4 by oxidation of 5-aryl-3-oxopentanoic acid esters or amides 1 with manganese(III) acetate or cerium(IV) ammonium nitrate has been developed, based on the intramolecular homolytic substitution by α-dicarbonylalkyl radicals generated from high-valent metal β-dicarbonyl complexes.
- Citterio, Attilio,Pesce, Luca,Sebastiano, Roberto,Santi, Roberto
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- Overcoming the Deallylation Problem: Palladium(II)-Catalyzed Chemo-, Regio-, and Stereoselective Allylic Oxidation of Aryl Allyl Ether, Amine, and Amino Acids
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We report herein a Pd(II)/bis-sulfoxide-catalyzed intramolecular allylic C-H acetoxylation of aryl allyl ether, amine, and amino acids with the retention of a labile allyl moiety. Mechanistically, the reaction proceeds through a distinct double-bond isomerization from the allylic to the vinylic position followed by intramolecular carboxypalladation and the β-hydride elimination pathway. For the first time, C-H oxidation of N-allyl-protected amino acids to furnish five-membered heterocycles through 1,3-syn-addition is established with excellent diastereoselectivity.
- Begam, Hasina Mamataj,Jana, Ranjan,Manna, Kartic,Samanta, Krishanu
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supporting information
p. 7443 - 7449
(2020/10/09)
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- Ruthenium(II)-catalyzed synthesis of hydroxylated arenes with ester as an effective directing group
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An unprecedented Ru(II) catalyzed ortho-hydroxylation has been developed for the facile synthesis of a variety of multifunctionalized arenes from easily accessible ethyl benzoates with ester as an efficient directing group. Both the TFA/TFAA cosolvent system and oxidants serve as the critical success factors in this transformation. The reaction demonstrates excellent reactivity, good functional group tolerance, and high yields.
- Yang, Yiqing,Lin, Yun,Rao, Yu
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supporting information; experimental part
p. 2874 - 2877
(2012/07/28)
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- Direct synthesis of esters and amides from unprotected hydroxyaromatic and -aliphatic carboxylic acids
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A facile method for the activation of hydroxy-substituted carboxylic acids using benzotriazole chemistry without prior protection of the hydroxy substituents is presented. The N-acylbenzotriazole intermediates 2a-g, 6a-d, and 9a-c have been used for high-yielding synthesis of both aliphatic (3a-1) and aromatic (7a-h, 10a-f) hydroxy carboxamides. High yields of aromatic hydroxy esters 12a-h and 13a-i were obtained using either neat alcohols in neutral microwave conditions or nucleophilic alkoxides and the intermediate N-(arylacyl)benzotriazoles. Moderate yields were obtained in the case of aliphatic hydroxy esters 11a,b and thiolesters 11e-g from the intermediates 2a-c.
- Katritzky, Alan R.,Singh, Sanjay K.,Cai, Chunming,Bobrov, Sergey
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p. 3364 - 3374
(2007/10/03)
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- A new method for the synthesis of 2-cyclopenten-1-one-5-carboxylic ester derivatives via Rh2(OAc)4-mediated intramolecular C-H insertion reaction of 4Z-β-vinyl-α-diazo β-ketoesters
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2-Cyclopenten-1-one-5-carboxylic ester derivatives 14 are synthesized in a four-step-reaction sequence starting from alkynyl aldehydes 9 via 4Z-β-vinyl-α-diazo β-ketoesters intermediate 8. The synthetic method for 8 is described. When the δ substituent is
- Deng, Guisheng,Xu, Baihua,Wang, Jianbo
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p. 10811 - 10817
(2007/10/03)
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