2049-96-9Relevant academic research and scientific papers
CH-π Interaction as an Important Driving Force of Host-Guest Complexation. Further Evidence for the Selective Incorporation of Alkyl Groups in the Polyhydroxy Aromatic Cavity of Calix[4]resorcarene Host
Kikuchi, Yasuaki,Aoyama, Yasuhiro
, p. 217 - 220 (1996)
The complexation of a calix[4]resorcarene host (2,8,14,20-tetraundecylcalix[4]arene-4,6,10,12,16,18,22,24-octol) with borneol in benzene or alkylbenzene was investigated by circular dichroism (CD) spectroscopy. The binding constants are dramatically solvent-dependent and decrease with respect to the substituents on the benzene ring in the order H>methyl>ethyl>propyl>butyl. The complexation of the same host with alkyl benzoates in limonene as a chiral hydrocarbon solvent was readily monitored by following their competitive inhibition effects on the CD intensities, reflecting the chiral host-solvent interaction. The binding constants for alkyl benzoates were again highly dependent on the alkyl groups, and changed in the order decylhexylmethylpropyl≈pentyl?butyl. There is thus an optimal chain length at butyl. These results provide further evidence for the selective incorporation of alkyl groups in the polyhydroxy aromatic cavity of the host.
Macrolactonization Reactions Driven by a Pentafluorobenzoyl Group**
Ciofini, Ilaria,Force, Guillaume,Leb?uf, David,Mayer, Robert J.,Perfetto, Anna
supporting information, p. 19843 - 19851 (2021/08/13)
Macrolactones constitute a privileged class of natural and synthetic products with a broad range of applications in the fine chemicals and pharmaceutical industry. Despite all the progress made towards their synthesis, notably from seco-acids, a macrolactonization promoter system that is effective, selective, flexible, readily available, and, insofar as possible, compatible with manifold functional groups is still lacking. Herein, we describe a strategy that relies on the formation of a mixed anhydride incorporating a pentafluorophenyl group which, due to its high electronic activation enables a convenient access to macrolactones, macrodiolides and esters with a broad versatility. Kinetic studies and DFT computations were performed to rationalize the reactivity of the pentafluorophenyl group in macrolactonization reactions.
LiHMDS: Facile, highly efficient and metal-free transesterification under solvent-free condition
Gore, Kiran R.,Mittapelli, Lavanya L.
, (2020/10/27)
Transesterification is one of the important organic reactions employed in numerous industrial as well as laboratory applications for the synthesis of various esters. Herein, we report a rapid, highly efficient, and transition metal-free transesterification reaction in the presence of LiHMDS under solvent-free conditions. The transesterification reaction was carried out with three different benzoate esters and a wide range of primary and secondary alcohols (from C3-C18) in good to excellent yields (45 examples). By considering the commercial role of esters, this method will be promising for the facile synthesis of esters in industry-relevant applications.
Erratum: Ruthenium-catalyzed C-H hydroxylation in aqueous acid enables selective functionalization of amine derivatives (Journal of the American Chemical Society (2017) 139:28 (9503-9506) DOI: 10.1021/jacs.7b05469)
Mack, James B.C.,Gipson, John D.,Du Bois,Sigman, Matthew S.
supporting information, p. 3016 - 3016 (2021/03/01)
Page 9504. The structure of product 3cc in Table 2 was found to be mis-assigned. We thank Prof. Phil Baran and Dr. Rafael Navratil for bringing this error to our attention. The correct structure contains an additional benzylic alcohol at the C-9 position of the steroid (3cc′, shown below). With the accompanying change in molecular weight, the isolated yield is 29%. Supporting Information. The incorrect structure and yield also appeared on pages S20 and S84 in the SI. Given this, the HRMS entry on page S20 should read as follows: “HRMS (ESI-TOF) m/z calcd for C19H18F3O5S+ (M-O+Na)+ 415.0822, found 415.0857”. The complete corrected SI is provided here.
N-Ammonium Ylide Mediators for Electrochemical C-H Oxidation
Saito, Masato,Kawamata, Yu,Meanwell, Michael,Navratil, Rafael,Chiodi, Debora,Carlson, Ethan,Hu, Pengfei,Chen, Longrui,Udyavara, Sagar,Kingston, Cian,Tanwar, Mayank,Tyagi, Sameer,McKillican, Bruce P.,Gichinga, Moses G.,Schmidt, Michael A.,Eastgate, Martin D.,Lamberto, Massimiliano,He, Chi,Tang, Tianhua,Malapit, Christian A.,Sigman, Matthew S.,Minteer, Shelley D.,Neurock, Matthew,Baran, Phil S.
supporting information, p. 7859 - 7867 (2021/05/26)
The site-specific oxidation of strong C(sp3)-H bonds is of uncontested utility in organic synthesis. From simplifying access to metabolites and late-stage diversification of lead compounds to truncating retrosynthetic plans, there is a growing need for new reagents and methods for achieving such a transformation in both academic and industrial circles. One main drawback of current chemical reagents is the lack of diversity with regard to structure and reactivity that prevents a combinatorial approach for rapid screening to be employed. In that regard, directed evolution still holds the greatest promise for achieving complex C-H oxidations in a variety of complex settings. Herein we present a rationally designed platform that provides a step toward this challenge using N-ammonium ylides as electrochemically driven oxidants for site-specific, chemoselective C(sp3)-H oxidation. By taking a first-principles approach guided by computation, these new mediators were identified and rapidly expanded into a library using ubiquitous building blocks and trivial synthesis techniques. The ylide-based approach to C-H oxidation exhibits tunable selectivity that is often exclusive to this class of oxidants and can be applied to real-world problems in the agricultural and pharmaceutical sectors.
Electrochemical esterification via oxidative coupling of aldehydes and alcohols
Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
supporting information, (2021/03/26)
An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
Palladium-Catalyzed Para-Selective Difluoromethylation of Arene Esters
Tu, Guangliang,Wang, Dongjie,Yuan, Chunchen,Zhang, Jingyu,Zhao, Yingsheng
, p. 10740 - 10749 (2020/09/18)
Highly efficient, palladium-catalyzed, para-selective difluoromethylation of arene esters has been developed using [1,1′-biphenyl]-2-dicyclohexylphosphine as the effective ligand. A wide variety of arene esters bearing various functional groups were all compatible with the reaction conditions, leading to para-difluoromethylated products in moderate to good yields. Moreover, benzoylamide and benzenesulfonamide were also well-tolerated, suggesting that this novel catalyst system has broad applications to a variety of substrates.
Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
supporting information, p. 8143 - 8146 (2020/09/09)
The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
Preparation, structure, and reactivity of bicyclic benziodazole: A new hypervalent iodine heterocycle
Jarvi, Melissa E.,Makitalo, Cody L.,Rohde, Gregory T.,Saito, Akio,Shea, Michael T.,Yoshimura, Akira,Yusubov, Mekhman S.,Zhdankin, Viktor V.
supporting information, p. 1016 - 1020 (2020/05/06)
A new bicyclic organohypervalent iodine heterocycle derivative of benziodazole was prepared by oxidation of 2-iodo-N,N'-diiso-propylisophthalamide with m-chloroperoxybenzoic acid under mild conditions. Single crystal X-ray crystallography of this compound revealed a five-membered bis-heterocyclic structure with two covalent bonds between the iodine atom and the nitrogen atoms. This novel benziodazole is a very stable compound with good solubility in common organic solvents. This compound can be used as an efficient reagent for oxidatively assisted coupling of carboxylic acids with alcohols or amines to afford the corresponding esters or amides in moderate yields.
1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions
Khosravi, Kaveh,Naserifar, Shirin
, p. 6584 - 6592 (2018/10/05)
Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.
