35632-82-7Relevant academic research and scientific papers
Enantioselective Cyclobutenylation of Olefins Using N-Sulfonyl-1,2,3-Triazoles as Vicinal Dicarbene Equivalents
Burns, Noah Z.,Mercer, Jaron A. M.,Patel, Sajan C.,Smith, Myles W.,Suzuki, Kensuke
supporting information, p. 6530 - 6535 (2021/09/02)
Cyclobutenes are highly useful synthetic intermediates as well as important motifs in bioactive small molecules. Herein, we report a regio-, chemo-, and enantioselective synthesis of cyclobutenes from olefins using N-sulfonyl-1,2,3-triazoles as vicinal dicarbene equivalents or alkyne [2 + 2] cycloaddition surrogates. Terminal and cis-olefins can be transformed into enantioenriched cyclopropanes via rhodium catalysis. Then, in one pot, treatment of these intermediates with tosyl hydrazide and base effects diazo formation followed by rhodium-catalyzed ring expansion to yield enantioenriched cyclobutenes. These cyclobutenes can be transformed into highly substituted, enantioenriched cyclobutanes, including structures relevant to natural product scaffolds.
Highly-functionalized arene synthesis based on palladium on carbon-catalyzed aqueous dehydrogenation of cyclohexadienes and cyclohexenes
Yasukawa, Naoki,Yokoyama, Hiroki,Masuda, Masahiro,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
, p. 1213 - 1217 (2018/03/28)
Transition metal-catalyzed dehydrogenation is a clean oxidation method requiring no additional oxidants. We have accomplished a heterogeneous Pd/C-catalyzed aqueous dehydrogenation of 1,4-cyclohexadienes and cyclohexenes to give the corresponding highly-functionalized arenes. Furthermore, various arenes could be efficiently constructed in a one-pot manner via a Diels-Alder reaction and the following dehydrogenation.
Zinc(II)-Catalyzed Asymmetric Diels-Alder Reaction of (E)-1-Phenyl Dienes with β,γ-Unsaturated α-Ketoesters
Xiong, Qian,Lin, Lili,Zhao, Xiaohu,Lang, Jiawen,Liu, Xiaohua,Feng, Xiaoming
, p. 12527 - 12534 (2018/10/20)
A highly regio-, diastereo-, and enantioselective Diels-Alder reaction of β,γ-unsaturated α-ketoesters with (E)-1-phenyl dienes has been accomplished by using a stable and easily available chiral N,N′-dioxide/zinc(II) complex as catalyst. Only one isomer of the corresponding cyclohexenes with three chiral centers was obtained in good to excellent yields with excellent ee values under mild reaction conditions. The configurations of the product and chiral N,N′-dioxide/zinc(II) catalyst were identified by X-ray diffraction analysis. In addition, a possible catalytic model was proposed to explain the origin of the asymmetric induction.
Synthesis of 1,3-Dienes via a Sequential Suzuki-Miyaura Coupling/Palladium-Mediated Allene Isomerization Sequence
Al-Jawaheri, Yassir,Kimber, Marc C.
supporting information, p. 3502 - 3505 (2016/07/23)
We report a facile method for the synthesis of 1,3-dienes by a sequential process consisting of a palladium-catalyzed, base-free, Suzuki-Miyaura coupling/isomerization sequence. This sequence couples boronic acids with propargyl alcohols, generating the requisite allene in situ, followed by conversion of the unactivated allene to its 1,3-diene via a hydro-palladation/dehydro-palladation process. This process is general for a range of boronic acids, including boronic acids with electron-donating and -withdrawing groups, as well as heteroarylboronic acids. Key to this process is the boric acid byproduct of the base-free Suzuki-Miyauru coupling, which generates the required palladium-hydrido complex [H-PdII-OB(OH)2] required for the isomerization.
Stereoselective synthesis of 1,3-dienes from propargylic alcohols by LiAlH4/AlCl3
Cui, Dong-Mei,Zhu, Kai,Chen, Li,Qi, Lang-Jun,Zhang, Cheng-Zhu,Zheng, Chen
supporting information, p. 2380 - 2384 (2013/07/26)
Herein we report that LiAlH4/AlCl3 is a very efficient reagent for the reductive dehydration of aryl propargylic alcohols in tetrahydrofuran solvent at reflux to give 1,3-dienes with good yields and high E selection. The reaction con
Gold-catalyzed isomerization of unactivated allenes into 1,3-dienes under ambient conditions
Ting, Chun-Ming,Hsu, Yi-Ling,Liu, Rai-Shung
supporting information; experimental part, p. 6577 - 6579 (2012/07/31)
We have developed a gold-catalyzed isomerization of unactivated allenes into 1,3-dienes with nitrosobenzene as an additive. This reaction proceeded almost exclusively at room temperature for highly substituted allenes. The utility of this reaction is manifested by the development of one-pot [4+2]-cycloaddition of allenes and reactive alkenes.
Aqueous sodium hydroxide promoted cross-coupling reactions of alkenyltrialkoxysilanes under ligand-free conditions
Alacid, Emilio,Najera, Carmen
, p. 2315 - 2322 (2008/09/19)
(Chemical Equation Presented) Fluoride-free cross-coupling reactions of alkenyltrialkoxysilanes with aryl iodides, bromides, and chlorides are performed on water using sodium hydroxide as activator at 120 °C under normal or microwave heating. This process occurs in the presence of Pd(OAc)2 or 4-hydroxyacetophenone oxime-derived palladacycle 1 as precatalysts under ligand-free conditions with low Pd loadings (0.01-1 mol %) and using tetra-n-butylammonium bromide as additive. Different commercially available vinylalkoxylsilanes can be cross-coupled under these reaction conditions to the corresponding styrenes, the best substrates being vinyltrimethoxy- or vinyltriethoxysilane. Alkenyltriethoxysilanes, prepared by Wilkinson-catalyzed hydrosilylation of alkynes with triethoxysilane, are stereospecifically arylated with aryl and vinyl halides under microwave irradiation in moderate to high β/α regioselectivity affording unsymmetrical stilbenes, alkenylbenzenes, and conjugate dienes, respectively. This simple procedure allows the palladium recycling from the aqueous phase during three runs by extractive separation of the products, which contain very low levels of Pd (21-27.5 ppm for an aryl iodide and up to 76 ppm for a bromide).
Reduction of Cp2ZrCl2 with mischmetall: A new method for generating an efficient "Cp2Zr" equivalent
Denhez, Clement,Medegan, Sedami,Helion, Florence,Namy, Jean-Louis,Vasse, Jean-Luc,Szymoniak, Jan
, p. 2945 - 2947 (2007/10/03)
A "Cp2Zr" equivalent is generated under mild conditions (THF, room temperature) by reducing Cp2ZrCl2 with cheap and readily available mischmetall (an alloy of Ce, La, Nd, and Pr). Coupling reactions, including those of terminal alkynes, can efficiently be achieved by using this reagent.
Decarbonylative Heck olefination of enol esters: Salt-free and environmentally friendly access to vinyl arenes
Goossen, Lukas J.,Paetzold, Jens
, p. 1095 - 1098 (2007/10/03)
Thank you, no salt on the side. In this variant of the Heck olefination, enol esters serve as environmentally friendly synthetic equivalents of aryl halides. These reactants, in turn, are available from a waste-free synthesis from carboxylic acids and propyne. Thus, a salt-free overall process has been devised for preparing vinyl arenes from a variety of aromatic carboxylic acids.
A stable β-silyl carbocation with allyl conjugation
Lambert, Joseph B.,Liu, Chunqing,Kouliev, Timur
, p. 667 - 671 (2007/10/03)
Phenyl group replaced by a double bond yielding a stable β-silyl carbocation was studied. Two systems were examined in which positive charge could be stabilized by one phenyl and one double bond or two double bonds. The carbocation was found to be stable at room temperature with tetrakis(pentafluorophenyl)borate as the anion benzene as the solvents. The range of β-silyl carbocations observed under stable ion conditions was relatively circumscribed.
