15781-96-1Relevant articles and documents
Rh(I)-Catalyzed C6-Selective Decarbonylative Alkylation of 2-Pyridones with Alkyl Carboxylic Acids and Anhydrides
Fan, Qinghua,Li, Bohan,Li, Huanrong,Walsh, Patrick J.,Xu, Lijin,Xu, Xin,Xu, Xingyu,Yu, Haiyang,Zhao, Haoqiang
, p. 4228 - 4234 (2020)
A Rh-catalyzed chelation-assisted C6-selective C-H activation/alkylation of 2-pyridones with readily available alkyl carboxylic acids or anhydrides is introduced. The reaction proceeds via substrate decarbonylation. This approach merges C-H functionalization with readily available anhydrides, allowing for the efficient synthesis of various C6-alkylated 2-pyridones with good functional group tolerance.
Unanticipated Silyl Transfer in Enantioselective α,β-Unsaturated Acyl Ammonium Catalysis Using Silyl Nitronates
Matviitsuk, Anastassia,Greenhalgh, Mark D.,Taylor, James E.,Nguyen, Xuan B.,Cordes, David B.,Slawin, Alexandra M. Z.,Lupton, David W.,Smith, Andrew D.
supporting information, p. 335 - 339 (2020/01/11)
The use of silyl nitronates is reported for the isothiourea-catalyzed synthesis of ?3-nitro-substituted silyl esters containing up to two contiguous stereocenters in good yields with excellent enantioselectivities (up to 93% yield and 99:1 er). The serendipitously discovered formation of silyl ester products in this reaction demonstrates a novel platform for catalyst turnover in α,β-unsaturated acyl ammonium catalysis.
Isothiourea-Catalyzed Atroposelective N-Acylation of Sulfonamides
Ong, Jun-Yang,Ng, Xiao Qian,Lu, Shenci,Zhao, Yu
supporting information, p. 6447 - 6451 (2020/09/02)
We report herein an atroposelective N-acylation of sulfonamides using a commercially available isothiourea catalyst, (S)-HBTM, with a simple procedure. The N-sulfonyl anilide products can be obtained in good to high enantiopurity, which represents a new axially chiral scaffold. The application of the product as a chiral iodine catalyst is also demonstrated for the asymmetric α-oxytosylation of propiophenone.
Isothiourea-Catalysed Regioselective Acylative Kinetic Resolution of Axially Chiral Biaryl Diols
Qu, Shen,Greenhalgh, Mark D.,Smith, Andrew D.
supporting information, p. 2816 - 2823 (2019/02/05)
An operationally simple isothiourea-catalysed acylative kinetic resolution of unprotected 1,1′-biaryl-2,2′-diol derivatives has been developed to allow access to axially chiral compounds in highly enantioenriched form (s values up to 190). Investigation of the reaction scope and limitations provided three key observations: i) the diol motif of the substrate was essential for good conversion and high s values; ii) the use of an α,α-disubstituted mixed anhydride (2,2-diphenylacetic pivalic anhydride) was critical to minimize diacylation and give high selectivity; iii) the presence of substituents in the 3,3′-positions of the diol hindered effective acylation. This final observation was exploited for the highly regioselective acylative kinetic resolution of unsymmetrical biaryl diol substrates bearing a single 3-substituent. Based on the key observations identified, acylation transition state models have been proposed to explain the atropselectivity of this kinetic resolution.
Photochemical Asymmetric Nickel-Catalyzed Acyl Cross-Coupling
Gandolfo, Eugenio,Tang, Xinjun,Raha Roy, Sudipta,Melchiorre, Paolo
supporting information, p. 16854 - 16858 (2019/11/11)
Photochemical enantioselective nickel-catalyzed cross-coupling reactions are difficult to implement. We report a visible-light-mediated strategy that successfully couples symmetrical anhydrides and 4-alkyl dihydropyridines (DHPs) to afford enantioenriched α-substituted ketones under mild conditions. The chemistry does not require exogenous photocatalysts. It is triggered by the direct excitation of DHPs, which act as a radical source and as a reductant, facilitating the turnover of the chiral catalytic nickel complex.
Visible light-induced transformation of aldehydes to esters, carboxylic anhydrides and amides
Gaspa, Silvia,Raposo, Inês,Pereira, Leonor,Mulas, Gabriele,Ricci, Pier Carlo,Porcheddu, Andrea,De Luca, Lidia
supporting information, p. 10711 - 10715 (2019/07/15)
A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields.
Metal-free oxidative self-coupling of aldehydes or alcohols to symmetric carboxylic anhydrides
Gaspa, Silvia,Porcheddu, Andrea,De Luca, Lidia
supporting information, p. 2533 - 2536 (2017/06/13)
A metal-free synthesis of symmetrical anhydrides has been developed starting from aldehydes, both aliphatic and aromatic or primary benzylic alcohols. The reaction occurs at room temperature and makes use of trichloroisocyanuric acid (TCCA) as an oxidant providing the desired carboxylic anhydrides in satisfactory yields.
Anhydrides from aldehydes or alcohols via oxidative cross-coupling
Gaspa, Silvia,Amura, Ida,Porcheddu, Andrea,De Luca, Lidia
supporting information, p. 931 - 939 (2017/02/10)
A novel type of metal-free oxidative cross-coupling for the synthesis of symmetrical and mixed anhydrides from aldehydes or benzylic alcohols has been developed. The aldehydes or alcohols were converted in situ into their corresponding acyl chlorides, which were then reacted with an array of carboxylic acids. The methodology has a general applicability, and was successfully employed to prepare either aromatic or aliphatic symmetrical anhydrides and mixed anhydrides, which are very unstable compounds.
Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
, p. 1972 - 1978 (2015/02/19)
We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
Convenient peptide synthesis without protection of C-Terminals
Noguchi, Takuya,Tehara, Naoka,Uesugi, Yuki,Jung, Seunghee,Imai, Nobuyuki
, p. 42 - 43 (2012/03/11)
Condensation of carboxylic acids 1 and 5 with unprotected α-amino acids 2 via activation by ethyl chloroformate and triethylamine proceeded effectively to afford the corresponding amides in 5099% yields. Tripeptide 7c was obtained in 42% yield from the dipeptide 6c in a similar manner.