- Stabilization and activation of unstable propynal in the zeolite nanospace and its application to addition reactions
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Propynal (HC≡C-CHO), having both a C≡C triple bond and a formyl group in a molecule, is a promising building block but its labile property to easily polymerize often narrows its application for organic synthesis. In a similar way to unstable molecules, such as formaldehyde and acrolein, propynal is also stabilized and remains unchanged in supercages of Na-Y zeolite for over 30 days at ambient temperature. There, the carbonyl oxygen atoms of propynal coordinate to sodium ions in Na-Y which was proved by a 13C-DD/MAS-NMR analysis. In addition, propynal adsorbed in zeolite is sufficiently activated to allow unprecedented reactions; i.e., (1) a 1,3-dipolar cycloaddition with electron-deficient α-diazocarbonyl compounds, (2) a 1,4-addition with mono-, di-, and trimethoxy-substituted benzenes, and (3) a [2 + 2] cycloaddition of unactivated cycloalkenes. The nanospace of the zeolites keeps the products from dimerization during reaction (1) and from successive side-reactions in reaction (2). Quantum chemical calculations demonstrated that reaction (3) proceeds via a one-step-like non-concerted mechanism to afford the corresponding [2 + 2] cycloadducts. These three reactions can produce valuable synthetic intermediates retaining both a formyl group and a C=C double bond.
- Hayashi, Daijiro,Igura, Yuta,Masui, Yoichi,Onaka, Makoto
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- Method for synthesizing 2 -methoxycinnamaldehyde
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The invention provides a synthetic method of 2 -methoxycinnamaldehyde, and belongs to the technical field of organic synthesis. The synthesis method provided by the invention comprises the following steps: (1) methylation reaction of 2 - hydroxybenzaldehyde and a methylation reagent under the action of a quaternary ammonium salt catalyst to obtain 2 - methoxybenzaldehyde. (2) Under alkaline conditions, 2 - methoxybenzaldehyde is subjected to a condensation reaction with acetaldehyde to obtain 2 -methoxycinnamaldehyde. 2 - Hydroxybenzaldehyde is used as a starting material, and the method has the advantages of wide sources and low cost. The method has the advantages of short synthetic route and less side reaction, and the obtained 2 -methoxycinnamaldehyde has high yield and purity and is suitable for industrial popularization and application. The results show that the yield 2 - and the purity ≥ 90% of ≥ 95% -methoxycinnamaldehyde obtained by the synthesis method provided by the invention are high.
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- Method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and diphosphine ligand used in method
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The invention discloses a method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and a diphosphine ligand used in the method. According to the invention, indole-substituted phosphoramidite diphosphine ligand which is stable in air and insensitive to light is synthesized by utilizing a continuous one-pot method, and the indole-substituted phosphoramidite diphosphine ligand and a rhodium catalyst are used for jointly catalyzing to successfully achieve a hydroformylation reaction of aromatic terminal alkyne and terminal conjugated eneyne under the condition of synthesis gas for the first time, so that an olefine aldehyde structure compound can be rapidly and massively prepared, and particularly, a polyolefine aldehyde structure compound which is more difficult to synthesize in the prior art can be easily prepared and synthesized, and a novel method is provided for synthesis and modification of drug molecules, intermediates and chemical products.
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Paragraph 0149-0154
(2021/05/29)
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- Highly Regio- A nd Enantioselective Hydrogenation of Conjugated α-Substituted Dienoic Acids
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Highly regio- A nd enantioselective hydrogenation of conjugated α-substituted dienoic acids was realized for the first time using Trifer-Rh complex, providing a straightforward method for the synthesis of chiral α-substituted ?,?′-unsaturated acids. DFT calculations revealed N+H-O hydrogen bonding interaction is formed to stabilize the transition state and the coordination of 4,5-double bond to Rh(III) center would facilitate the reductive elimination process. This hydrogenation provided a gram-scale synthesis of the precursor of sacubitril.
- Liu, Xian,Liu, Song,Wang, Quanjun,Zhou, Gang,Yao, Lin,Ouyang, Qin,Jiang, Ru,Lan, Yu,Chen, Weiping
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supporting information
p. 3149 - 3154
(2020/04/09)
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- Highly Enantioselective Synthesis of Functionalized Glutarimide Using Oxidative N-Heterocyclic Carbene Catalysis: A Formal Synthesis of (?)-Paroxetine
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A simple yet highly effective approach toward enantioselective synthesis of trans-3,4-disubstituted glutarimides from readily available starting materials is developed using oxidative N-heterocyclic carbene catalysis. The catalytic reaction involves a formal [3 + 3] annulation between enals and substituted malonamides enabling the production of glutarimide derivatives in a single chemical operation via concomitant formation of C-C and C-N bonds. The reaction offers easy access to a broad range of functionalized glutarimides with excellent enantioselectivity and good yield. Synthetic application of the method is demonstrated via formal synthesis of (?)-paroxetine and other bioactive molecules.
- Porey, Arka,Santra, Surojit,Guin, Joyram
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supporting information
p. 5313 - 5327
(2019/04/16)
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- Palladium-catalyzed salt-free double decarboxylative aryl allylation
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This report describes a palladium-catalyzed decarboxylative aryl allylation between unactivated benzoic acids and allylic carbonates. This transformation successfully couples a variety of carbonates and benzoic acids in good yield (up to 94%) using 1 mol% palladium. This salt free allyl-arylation proceeds without added base, copper, or silver. The only stoichiometric byproducts are carbon dioxide and tert-butanol.
- Daley, Ryan A.,Topczewski, Joseph J.
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supporting information
p. 1709 - 1713
(2019/02/20)
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- Copper-catalyzed formylation of alkenyl C-H bonds using BrCHCl2 as a stoichiometric formylating reagent
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The first example of copper-catalyzed direct formylation of alkenyl C-H bonds for the facile synthesis of α,β-unsaturated aldehydes has been developed. This transformation has demonstrated high reactivity, mild reaction conditions and a broad substrate scope. BrCHCl2 is expected to be developed as an efficient stoichiometric C1 building block in organic synthesis.
- Bao, Yan,Wang, Gao-Yin,Zhang, Ya-Xuan,Bian, Kang-Jie,Wang, Xi-Sheng
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p. 2986 - 2990
(2018/03/23)
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- Dehydrogenative Synthesis of Linear α,β-Unsaturated Aldehydes with Oxygen at Room Temperature Enabled by tBuONO
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Synthesis of linear α,β-unsaturated aldehydes via a room-temperature oxidative dehydrogenation has been realized by the cocatalysis of an organic nitrite and palladium with molecular oxygen as the sole clean oxidant. Linear α,β-unsaturated aldehydes could be efficiently prepared under aerobic catalytic conditions directly from the corresponding saturated linear aldehydes. Besides linear products, the aromatic analogy could also be smoothly achieved by the same standard method. The organic nitrite redox cocatalyst and alcohol solvent play a key role for realizing this method.
- Wang, Mei-Mei,Ning, Xiao-Shan,Qu, Jian-Ping,Kang, Yan-Biao
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p. 4000 - 4003
(2017/06/19)
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- Selectivity Modulation of the Ley–Griffith TPAP Oxidation with N-Oxide Salts
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A wide variety of novel non-hygroscopic N-oxide tetraphenylborate salts were synthesized and evaluated as co-oxidants in the Ley–Griffith (TPAP) oxidation of benzylic and allylic alcohols under non-anhydrous conditions. The novel DABCOO·TPB (2:1) salt was herein unearthed as a viable competitor to the first-generation NMO·TPB (2:1) salt, but more importantly gave increased performance under oxidative competition. X-ray crystal structure analysis and NMR spectroscopy revealed that depending on the crystallization conditions 1:1, 2:1 or 3:2 N-oxide–tetraphenylborate salts could be formed.
- Moore, Peter W.,Jiao, Yanxiao,Mirzayans, Paul M.,Sheng, Lexter Ng Qi,Hooker, Jordan P.,Williams, Craig M.
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p. 3401 - 3407
(2016/07/26)
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- Oxygenative and Dehydrogenative [3 + 3] Benzannulation Reactions of α,β-Unsaturated Aldehydes and γ-Phosphonyl Crotonates Mediated by Air: Regioselective Synthesis of 4-Hydroxybiaryl-2-carboxylates
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Regioselective synthesis of 4-hydroxybiphenyl-2-carboxylates via the base-mediated oxygenative [3 + 3] benzannulation reaction of α,β-unsaturated aldehydes and γ-phosphonyl crotonates is reported. A hydroxyl group is installed in the final product on the originally phosphorus-bound carbon via a novel oxygenative and dehydrogenative transformation. The reaction proceeds rapidly in an open flask, uses atmospheric oxygen as an oxidant, and affords good yields of substituted biaryl phenols. (Chemical Equation Presented).
- Joshi, Prabhakar Ramchandra,Nanubolu, Jagadeesh Babu,Menon, Rajeev S.
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supporting information
p. 752 - 755
(2016/03/01)
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- One-Pot Synthesis of (S)-Baclofen via Aldol Condensation of Acetaldehyde with Diphenylprolinol Silyl Ether Mediated Asymmetric Michael Reaction as a Key Step
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An efficient asymmetric total synthesis of (S)-baclofen was accomplished via a one-pot operation from commercially available materials using sequential reactions, such as aldol condensation of acetaldehyde, diphenylprolinol silyl ether mediated asymmetric Michael reaction of nitromethane, Kraus-Pinnick oxidation, and Raney Ni reduction. Highly enantioenriched baclofen was obtained in one pot with a good yield over four reactions.
- Hayashi, Yujiro,Sakamoto, Daisuke,Okamura, Daichi
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supporting information
p. 4 - 7
(2016/01/15)
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- Practical Cu(OAc)2/TEMPO-catalyzed selective aerobic alcohol oxidation under ambient conditions in aqueous acetonitrile
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We reported a ligand-and additive-free Cu(OAc)2/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary and secondary benzylic alcohols, primary and secondary 1-heteroaryl alcohols, cinnamyl alcohols, and aliphatic alcohols to the corresponding aldehydes and ketones. This ambient temperature oxidation protocol is of practical features like aqueous acetonitrile as solvent, ambient air as the terminal oxidant, and low catalyst loading, presenting a potential value in terms of both economical and environmental considerations. Based on the experimental observations, a plausible reaction mechanism was proposed.
- Jiang, Jian-An,Du, Jia-Lei,Wang, Zhan-Guo,Zhang, Zhong-Nan,Xu, Xi,Zheng, Gan-Lin,Ji, Ya-Fei
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supporting information
p. 1677 - 1681
(2014/03/21)
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- One-pot access to cinnamates via direct oxidative c-h transformation of allylarenes
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A highly selective combination of ruthenium complex and oxidant, which catalyzes the oxidative C-H esterification of allylarenes to the corresponding bis-(E)-cinnamates and (E)-cinnamates, is described. The one-pot route was carried out by olefinic migration of allylarenes with RuCl2(PPh 3)3 and DDQ-mediated allylic oxidation of the resulting internal alkenes with various alcohols in good yields. Georg Thieme Verlag Stuttgart · New York.
- Chang, Meng-Yang,Lin, Shin-Ying,Chan, Chieh-Kai
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p. 487 - 490
(2013/04/10)
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- ANALGESIC 5, 9 - METHANOCYCLOOCTA (b) PYRIDIN - 2 (1H) - ONE DERIVATIVES, THEIR PREPARATION METHOD AND USE
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Compounds represented by the Formula I or salts, hydrates thereof, wherein R1, R8, R11 and R12 are H or C1-4 hydrocarbonyl respectively; R2, R3, R6 and R7 are H, halogen or C1-4 hydrocarbonyl respectively; R4 is C1-6 hydrocarbonyl or Ar; or =CR4R3 is cyclopentylidene, cyclohexylidene, 1-methylpiperidyl-4-idene or indenyl-1-idene; R5 is H, 1-4 same or different F, Cl, Br, CF3, R9, OR9, NR9R10, NO2, CN, COOR9, O2CR9, CONR9R10, NR9C(O)R10, heterocyclic, aryl or groups represented by the Formula II respectively; R9 and R10 are H or C1-6 hydrocarbonyl; Ar is aromatic ring; m is 0, 1 or 2; n is 0, 1, 2, 3 or 4, for treating mammal pain, functional painful syndrome, organic painful syndrome or tissue painful syndrome, and their preparation method.
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Page/Page column 15
(2009/04/23)
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- Direct oxidation of β-aryl substituted aldehydes to α,β-unsaturated aldehydes promoted by an o-anisidine-Pd(OAc) 2 Co-catalyst
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An o-anisidine-Pd(OAc)2 catalytic system for the direct co-catalytic Saegusa oxidation of β-aryl substituted aldehydes to α,β-unsaturated aldehydes has been developed. The use of o-anisidine in place of (S)-diphenylprolinol made the process more simply and cost-effective. The process not only features the use of unmodified aldehydes rather than enol silyl ethers, but also gives moderate to good yields (44-72%).
- Liu, Jie,Zhu, Jin,Jiang, Hualiang,Wang, Wei,Li, Jian
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experimental part
p. 1712 - 1716
(2010/04/30)
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- A direct amine-palladium acetate cocatalyzed saegusa oxidation reaction of unmodified aldehydes to α,β-unsaturated aldehydes
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A direct preparation of synthetically useful α,β-unsaturated aldehydes from readily available aldehydes has been developed. The process is effectively cocatalyzed by an amine-palladium acetate to give rise to α,β-unsaturated aldehydes in moderate to good yields (41-62%). The reaction features the use of unmodified aldehydes rather than enol silyl ethers, which are used in a typical Saegusa oxidation reaction.
- Zhu, Jin,Liu, Jie,Ma, Ruoqun,Xie, Hexin,Li, Jian,Jiang, Hualiang,Wang, Wei
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supporting information; experimental part
p. 1229 - 1232
(2009/12/07)
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- Synthesis and biological activity of cinnamaldehydes as angiogenesis inhibitors
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A series of 2-hydroxycinnamaldehyde derivatives was synthesized for examing a structure-activity relationship for inhibition of angiogenesis. The anti-angiogenic effects of 2'-substituted cinnamaldehydes and related analogs were determined in a chick embryo chorioallantoic membrane assay system.
- Kwon, Byoung-Mog,Lee, Seung-Ho,Cho, Young-Kwon,Bok, Song-Hae,So, Seung-Ho,Youn, Mi-Ran,Chang, Soo-Ik
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p. 2473 - 2476
(2007/10/03)
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