13702-35-7Relevant academic research and scientific papers
Stereo- and Regioselective 1,3-Dipolar Cycloaddition of the Stable Ninhydrin-Derived Azomethine Ylide to Cyclopropenes: Trapping of Unstable Cyclopropene Dipolarophiles
Filatov, Alexander S.,Wang, Siqi,Khoroshilova, Olesya V.,Lozovskiy, Stanislav V.,Larina, Anna G.,Boitsov, Vitali M.,Stepakov, Alexander V.
, p. 7017 - 7036 (2019)
A stereo- and regioselective 1,3-dipolar cycloaddition of the stable ninhydrin-derived azomethine ylide [2-(3,4-dihydro-2H-pyrrolium-1-yl)-1-oxo-1H-inden-3-olate, DHPO] to differently substituted cyclopropenes has been established. As a result, an efficient synthetic protocol was developed for the preparation of biologically relevant spiro[cyclopropa[a]pyrrolizine-2,2′-indene] derivatives. DHPO has proved to be an effective trap for such highly reactive and unstable substrates as parent cyclopropene, 1-methylcyclopropene, 1-phenylcyclopropene, and 1-halo-2-phenylcyclopropenes. It has also been found that 3-nitro-1,2-diphenylcyclopropene undergoes a nucleophilic substitution reaction in alcohols and thiols to afford 3-alkoxy- and 3-arylthio-substituted 1,2-diphenylcyclopropenes, which can be captured as corresponding 1,3-dipolar cycloadducts in the presence of DHPO. These new approaches provide a straightforward strategy for the synthesis of functionally substituted cyclopropa[a]pyrrolizine derivatives. The factors governing regio- and stereoselectivity have been revealed by means of quantum mechanical calculations (M11 density functional theory), including previously unreported Nylide-Hcyclopropene second-orbital interactions. The outcome of this work contributes to the study of 1,3-dipolar cycloaddition, as well as enriches chemistry of cyclopropenes and methods for the construction of polycyclic compounds with cyclopropane fragments.
A stereoselective synthetic route to (Z)-α-stannyl-α,β-unsaturated aldehydes
Zhong,Xiong,Huang
, p. 3535 - 3541 (2000)
Acetylenic stannanes 1 react with Cp2Zr(H)Cl (Cp = η5-C5H5) and CO to give acylzirconocene chloride derivatives 2, which are trapped with dilute HCl to afford (Z)-α-stannyl-α,β-unsaturated aldehydes 3.
Carbocyclic ring expansions with alkyne and carbene sources mediated by nickel(0) complexes: Structure of the critical organonickel intermediates
Eisch, John J.,Aradi, Allen A.,Lucarelli, Michael A.,Qian, Yun
, p. 1169 - 1184 (1998)
Experimental evidence is assessed concerning the nature of organonickel intermediates involved in the cyclotrimerization and the cyclotetramerization of alkynes, as well as the cross-oligomerization of alkynes with carbene sources, as mediated by nickel(0) complexes. In the former processes a sequential series of nickelacycloalkapolyenes are the productive intermediates and in the latter cross-oligomerizations nickel(0)-carbene complexes themselves are critical precursors to the ultimately generated carbocycles.
Palladium-catalyzed ring-opening alkynylation of cyclopropenones
Matsuda, Takanori,Sakurai, Yusuke
, p. 4219 - 4222 (2013)
N-Heterocyclic carbene-palladium catalysts are used to promote addition/ring opening of cyclopropenones with terminal alkynes. The ring-opening alkynylation affords alkenyl alkynyl ketones in good yields. For reactions with propargylic esters having an ar
Cross β-arylmethylation of alcohols catalysed by recyclable Ti-Pd alloys not requiring pre-activation
Utsunomiya, Masayoshi,Kondo, Ryota,Oshima, Toshinori,Safumi, Masatoshi,Suzuki, Takeyuki,Obora, Yasushi
supporting information, p. 5139 - 5142 (2021/05/31)
Ti-Pd alloy catalysts were developed for the cross β-arylmethylation between arylmethylalcohols and different primary alcohols via a hydrogen autotransfer mechanism. The alloy catalysts could be reused multiple times without the need for pre-activation. Analysis of the reaction solution by inductively coupled plasma atomic absorption spectroscopy indicated that only a minimal amount of Ti and no Pd was leached from the catalyst.
Rhodium-Catalyzed Regioselective Hydroformylation of Alkynes to α,β-Unsaturated Aldehydes Using Formic Acid
Fan, Chao,Hou, Jing,Chen, Yu-Jia,Ding, Kui-Ling,Zhou, Qi-Lin
supporting information, p. 2074 - 2077 (2021/04/05)
A rhodium-catalyzed hydroformylation of alkynes with formic acid was developed. The method provides α,β-unsaturated aldehydes in high yield and E-selectivity without the need to handle toxic CO gas.
Complex Polyheterocycles and the Stereochemical Reassignment of Pileamartine A via Aza-Heck Triggered Aryl C-H Functionalization Cascades
Bower, John F.,Caiger, Lewis,García-Cárceles, Javier,Hazelden, Ian R.,Jones, Benjamin T.,Langer, Thomas,Lewis, Richard J.
supporting information, p. 15593 - 15598 (2021/10/12)
Structurally complex benzo- and spiro-fused N-polyheterocycles can be accessed via intramolecular Pd(0)-catalyzed alkene 1,2-aminoarylation reactions. The method uses N-(pentafluorobenzoyloxy)carbamates as the initiating motif, and this allows aza-Heck-type alkene amino-palladation in advance of C-H palladation of the aromatic component. The chemistry is showcased in the first total synthesis of the complex alkaloid (+)-pileamartine A, which has resulted in the reassignment of its absolute stereochemistry.
Biocatalytic reduction of α,β-unsaturated carboxylic acids to allylic alcohols
Aleku, Godwin A.,Leys, David,Roberts, George W.
, p. 3927 - 3939 (2020/07/09)
We have developed robust in vivo and in vitro biocatalytic systems that enable reduction of α,β-unsaturated carboxylic acids to allylic alcohols and their saturated analogues. These compounds are prevalent scaffolds in many industrial chemicals and pharmaceuticals. A substrate profiling study of a carboxylic acid reductase (CAR) investigating unexplored substrate space, such as benzo-fused (hetero)aromatic carboxylic acids and α,β-unsaturated carboxylic acids, revealed broad substrate tolerance and provided information on the reactivity patterns of these substrates. E. coli cells expressing a heterologous CAR were employed as a multi-step hydrogenation catalyst to convert a variety of α,β-unsaturated carboxylic acids to the corresponding saturated primary alcohols, affording up to >99percent conversion. This was supported by the broad substrate scope of E. coli endogenous alcohol dehydrogenase (ADH), as well as the unexpected CC bond reducing activity of E. coli cells. In addition, a broad range of benzofused (hetero)aromatic carboxylic acids were converted to the corresponding primary alcohols by the recombinant E. coli cells. An alternative one-pot in vitro two-enzyme system, consisting of CAR and glucose dehydrogenase (GDH), demonstrates promiscuous carbonyl reductase activity of GDH towards a wide range of unsaturated aldehydes. Hence, coupling CAR with a GDH-driven NADP(H) recycling system provides access to a variety of (hetero)aromatic primary alcohols and allylic alcohols from the parent carboxylates, in up to >99percent conversion. To demonstrate the applicability of these systems in preparative synthesis, we performed 100 mg scale biotransformations for the preparation of indole-3-aldehyde and 3-(naphthalen-1-yl)propan-1-ol using the whole-cell system, and cinnamyl alcohol using the in vitro system, affording up to 85percent isolated yield.
Tuning the Selectivity of Palladium Catalysts for Hydroformylation and Semihydrogenation of Alkynes: Experimental and Mechanistic Studies
Beller, Matthias,Ge, Yao,Jackstell, Ralf,Jiao, Haijun,Liu, Jiawang,Wei, Duo,Wei, Zhihong,Yang, Ji
, p. 12167 - 12181 (2020/11/27)
Here, we describe a selective palladium catalyst system for chemodivergent functionalization of alkynes with syngas. In the presence of an advanced ligand L2 bearing 2-pyridyl substituent as a built-in base, either hydroformylation or semihydrogenation of diverse alkynes occurs with high chemo- and stereoselectivity under comparable conditions. Mechanistic studies, including density functional theory (DFT) calculations, kinetic analysis, and control experiments, revealed that the strength and concentration of acidic cocatalysts play a decisive role in controlling the chemoselectivity. DFT studies disclosed that ligand L2 not only promotes heterolytic activation of hydrogen similar to frustrated Lewis pair (FLP) systems in the hydrogenolysis step for hydroformylation but also suppresses CO coordination to promote semihydrogenation under strong acid conditions. This switchable selectivity provides a strategy to design new catalysts for desired products.
Stereo-controlledanti-hydromagnesiation of aryl alkynes by magnesium hydrides
Chiba, Shunsuke,Li, Yihang,Ong, Derek Yiren,Pang, Jia Hao,Takita, Ryo,Wang, Bin,Watanabe, Kohei
, p. 5267 - 5272 (2020/06/04)
A concise protocol foranti-hydromagnesiation of aryl alkynes was established using 1?:?1 molar combination of sodium hydride (NaH) and magnesium iodide (MgI2) without the aid of any transition metal catalysts. The resulting alkenylmagnesium intermediates could be trapped with a series of electrophiles, thus providing facile accesses to stereochemically well-defined functionalized alkenes. Mechanistic studies by experimental and theoretical approaches imply that polar hydride addition from magnesium hydride (MgH2) is responsible for the process.
