6153-06-6Relevant academic research and scientific papers
Chiral 1,2,3-Triazolium Salt Catalyzed Asymmetric Mono- and Dialkylation of 2,5-Diketopiperazines with the Construction of Tetrasubstituted Carbon Centers
Yang, Ju-Song,Lu, Ka,Li, Chen-Xiao,Zhao, Zu-Hang,Zhang, Xiao-Ming,Zhang, Fu-Min,Tu, Yong-Qiang
supporting information, (2022/01/22)
Novel asymmetric mono- and dialkylation reactions of α-substituted 2,5-diketopiperazines catalyzed by new chiral spirocyclic-amide-derived triazolium organocatalysts have been developed, resulting in a range of enantioenriched 2,5-diketopiperazine derivatives containing one or two tetrasubstituted carbon stereocenters. The reactions feature high yields (up to 98%), and excellent cis-diastereo- and enantioselectivities (up to >20:1 dr, >99 % ee), and they provide a new asymmetric synthetic approach to important functionalized 2,5-diketopiperazine skeletons. Furthermore, a possible reaction mechanism was proposed based on both control experiments and extensive DFT calculations.
Atom-Economical Cross-Coupling of Internal and Terminal Alkynes to Access 1,3-Enynes
Liu, Mingyu,Tang, Tianhua,Apolinar, Omar,Matsuura, Rei,Busacca, Carl A.,Qu, Bo,Fandrick, Daniel R.,Zatolochnaya, Olga V.,Senanayake, Chris H.,Song, Jinhua J.,Engle, Keary M.
supporting information, p. 3881 - 3888 (2021/04/06)
Selective carbon-carbon (C-C) bond formation in chemical synthesis generally requires prefunctionalized building blocks. However, the requisite prefunctionalization steps undermine the overall efficiency of synthetic sequences that rely on such reactions, which is particularly problematic in large-scale applications, such as in the commercial production of pharmaceuticals. Herein, we describe a selective and catalytic method for synthesizing 1,3-enynes without prefunctionalized building blocks. In this transformation several classes of unactivated internal acceptor alkynes can be coupled with terminal donor alkynes to deliver 1,3-enynes in a highly regio- and stereoselective manner. The scope of compatible acceptor alkynes includes propargyl alcohols, (homo)propargyl amine derivatives, and (homo)propargyl carboxamides. This method is facilitated by a tailored P,N-ligand that enables regioselective addition and suppresses secondary E/Z-isomerization of the product. The reaction is scalable and can operate effectively with as low as 0.5 mol % catalyst loading. The products are versatile intermediates that can participate in various downstream transformations. We also present preliminary mechanistic experiments that are consistent with a redox-neutral Pd(II) catalytic cycle.
Synthetic study of an intermediate towards paracentrone
Kaneyama, Taiki,Fujimaru, Kazumi,Takemura, Mami,Hasegawa, Kizuku,Hamada, Masahiro,Kishimoto, Takao,Urabe, Daisuke,Nakajima, Noriyuki
, p. 281 - 294 (2019/08/01)
Paracentrone (1), the second naturally occurring C31-methyl ketone apocarotenoid from fucoxanthin (2), was first isolated from the sea urchin Paracentrotus lividus. In this study, we focused on this carotenoid metabolite and report on a synthetic approach towards (3E)-(5R)-[(2R,4S)-2-hydroxy-4-(tert-butyldimethylsilyl)oxy-2,6,6-trimethylcyclohexylidene]-1-iodo-4-methyl-1,3, 5-hexatriene (5), a synthetic intermediate towards 1. This was obtained from epoxy acetylene (11) via (2E)-(4R)-[(2R,4S)-2-hydroxy-4-(tert-butyldimethyl-silyl)oxy-2,6,6-trimethylcyclohexylidene]-3-methylpenta-2,4-dien-1-ol (7).
Chemoenzymatic one-pot reaction of noncompatible catalysts: Combining enzymatic ester hydrolysis with Cu(i)/bipyridine catalyzed oxidation in aqueous medium
Sand, Henning,Weberskirch, Ralf
, p. 33614 - 33626 (2017/07/12)
The combination of chemical catalysts and biocatalysts in a one-pot reaction has attracted considerable interest in the past years. However, since each catalyst requires very different reaction conditions, chemoenzymatic one-pot reactions in aqueous media remain challenging and are limited today to metal-catalysts that display high activity in aqueous media. Here, we report the first combination of two incompatible catalytic systems, a lipase based ester hydrolysis with a water-sensitive Cu/bipyridine catalyzed oxidation reaction, in a one-pot reaction in aqueous medium (PBS buffer). Key to the solution was the compartmentalization of the Cu/bipyridine catalyst in a core-shell like nanoparticle. We show the synthesis and characterization of the Cu/bipyridine functionalized nanoparticles and the application in the oxidation of allylic and benzylic alcohols in aqueous media. Furthermore, the work demonstrates the implementation of a one-pot reaction process with optimized reaction conditions involving a lipase (CAL-B) to hydrolyze various acetate ester substrates in the first step, followed by oxidation of the resulting alcohols to the corresponding aldehydes under aerobic conditions in aqueous media.
Extrapolation of the gold-catalyzed cycloisomerization to the palladium-catalyzed cross-coupling/cycloisomerization of acetylenic alcohols for the synthesis of polysubstituted furans: Scope and application to tandem processes
Praveen, Chandrasekar,Perumal, Paramasivan T.
, p. 288 - 299 (2016/02/23)
This paper describes the development of an integrated approach for the preparation of diverse furan derivatives from acetylenic alcohols by gold and palladium catalyzed π-activation chemistry. Notably, this new method was found to be amenable to cycloocty
Synthesis of C6 acetylenic alcohols
Pu, Shuai,Zhang, A.I. Gui,Zhang, Shao Feng,Wang, Y.U. Liang
, p. 635 - 638 (2015/02/18)
C6 acetylenic alcohols are important intermediates in the synthesis of Vitamin A and carotenoids. New synthesis methods of the C6 acetylenic alcohols and their four derivatives are reported. These designed synthesis methods are useful improvement to the present methodologies. Structures of these compounds are confirmed by 1H NMR, IR and mass spectra analysis.
Ruthenium-catalyzed functionalization of pyrroles and indoles with propargyl alcohols
Thies, Nora,Hrib, Cristian G.,Haak, Edgar
supporting information; experimental part, p. 6302 - 6308 (2012/06/18)
Several ruthenium-catalyzed atom-economic transformations of propargyl alcohols with pyrroles or indoles leading to alkylated, propargylated, or annulated heteroaromatics are reported. The mechanistically distinct reactions are catalyzed by a single ruthenium(0) complex containing a redox-coupled dienone ligand. The mode of activation regarding the propargyl alcohols determines the reaction pathway and depends on the alcohols' substitution pattern. Secondary substrates form alkenyl complexes by a 1,2-hydrogen shift, whereas the transformation of tertiary substrates involves allenylidene intermediates. 1-Vinyl propargyl alcohols are converted by a cascade allylation/cyclization sequence. The environmentally benign processes are of broad scope and allow the selective synthesis of highly functionalized pyrroles and indoles generating water as the only waste product. Copyright
Ruthenium-catalyzed allylation-cyclization reactions of cyclic 1,3-dicarbonyl compounds with 1-vinyl propargyl alcohols
Jonek, Anita,Berger, Stefanie,Haak, Edgar
, p. 15504 - 15511 (2013/01/15)
Ruthenium-catalyzed allylation-cyclization reactions of cyclic 1,3-dicarbonyl compounds with 1-vinyl propargyl alcohols that lead to diverse carbo- or heterocyclic products in a one-pot cascade process are reported. These mechanistically distinct reactions are catalyzed by a single ruthenium(0) complex that contains a redox-coupled dienone ligand. The reaction pathway strongly depends on the substrate substitution pattern, which determines the mode of activation of the 1-vinyl propargyl alcohol. The environmentally benign process, which generates water as the only waste product, is of wide scope and allows the atom-economic synthesis of highly functionalized furans, pyrans, and spirocarbocycles. Ring-producing expert: Ru complexes of redox-coupled cyclopentadienone ligands catalyze various allylation-cyclization reactions of cyclic 1,3-dicarbonyl compounds with 1-vinyl propargyl alcohols through strikingly distinct modes of activation to afford highly functionalized furans, pyrans, and spirocarbocycles (see scheme). Copyright
ORTHO-FLUORO SUBSTITUTED COMPOUNDS FOR THE TREATMENT OF METABOLIC DISEASES
-
Page/Page column 46-47, (2012/10/18)
There is provided novel fluoro-substituted compounds capable of modulating the G- protein-coupled receptor GPR40, compositions comprising the compounds, and methods for their use for controlling insulin levels in vivo and for the treatment of conditions such as type II diabetes, hypertension, ketoacidosis, obesity, glucose intolerance, and hypercholesterolemia and related disorders associated with abnormally high or low plasma lipoprotein, triglyceride or glucose levels.
Anodic oxidation: An attractive alternative to CAN-mediated cleavage of para-methoxyphenyl ethers
Vaxelaire, Carine,Souquet, Florence,Lannou, Marie-Isabelle,Ardisson, Janick,Royer, Jacques
supporting information; experimental part, p. 3138 - 3140 (2009/12/05)
para-Methoxyphenyl (PMP) ether is a very convenient protecting group for the alcohol function; however, its cleavage requires strong oxidative conditions. In this field, the use of powerful eerie ammonium nitrate has been widely described, despite the fac
