2100-17-6Relevant articles and documents
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Crandall,J.K.,Mayer,C.F.
, p. 3049 - 3053 (1970)
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Total Synthesis of Amphirionin-4
Ogura, Yusuke,Sato, Hikaru,Kuwahara, Shigefumi
, p. 2399 - 2402 (2016)
An expeditious enantioselective total synthesis of amphirionin-4, a remarkably potent promoter of the proliferation of ST-2 cells, has been achieved from (±)-(E)-1,4-hexadien-3-ol by an 8-pot sequence that features the Sharpless kinetic resolution, iodoetherification, and the CBS reduction to install the stereocenters, utilization of four one-pot transformations to streamline the synthetic process, and the Stille coupling reaction at nearly the center of the target molecule to complete the total synthesis.
Direct observation of the molecular structural changes during the claisen rearrangement including the transition state
Iwakura, Izumi,Yabushita, Atushi,Kobayashi, Takayoshi
, p. 374 - 375 (2010)
The detailed processes in the Claisen rearrangement were observed. The process was vibrationally excited in the electronic ground state by a stimulated Raman process using a 5-fs pulse. The Claisen rearrangement was found to follow a three-step pathway. At first, the C4-O bond is weakened to generate a bisallyl-like intermediate. Next, the formation of a weak C 1-C6 bond results in the generation of an aromatic-like intermediate. Finally, C4-O breaking and C1-C6 formation occur simultaneously to generate the product.
Asymmetric synthesis of the main core of kaurane family members triggered by an oxidative polycyclization-pinacol tandem process
Desjardins, Samuel,Maertens, Ga?tan,Canesi, Sylvain
, p. 4928 - 4931 (2014)
Polycyclization processes represent expeditious routes used in both nature and the laboratory to produce complex polycyclic molecules. A new stereoselective oxidative variant of such a polycyclization has been developed in which the cascade is triggered by a phenol dearomatization and is concluded by a pinacol transposition. This unprecedented avenue combines the synthetic power of a polycyclization and a transposition in tandem and enables the rapid formation of the tetracyclic main core of kaurane diterpenes containing several asymmetric and quaternary carbon centers in a single step from a simple phenol derivative.
Towards novel difluorinated sugar mimetics; syntheses and conformational analyses of highly-functionalised difluorinated cyclooctenones
Griffith, Gerry A.,Percy, Jonathan M.,Pintat, Stephane,Smith, Clive A.,Spencer, Neil,Uneyama, Emi
, p. 2701 - 2712 (2005)
Highly-functionalised difluorinated cyclooctenones were synthesised from trifluoroethanol using either metallated difluoroenol acetal or carbamate chemistry, followed by a [2,3]-Wittig rearrangement or aldol reaction. Efficient RCM reactions afforded the title compounds which showed rather restricted fluxional behaviour by VT 19F NMR. Topological characterisation by molecular modelling and NOESY/ROESY experiments offered a number of challenges, but allowed the identification of two favoured boat-chair conformers which interconverted by pseudorotation with relatively large activation barriers. The Royal Society of Chemistry 2005.
Blades
, p. 2269,2270 (1970)
Selective hydroformylation of open-chain conjugated dienes promoted by mesitylene-solvated rhodium atoms to give β,γ unsaturated monoaldehydes
Bertozzi, Sergio,Campigli, Nedo,Vitulli, Giovanni,Lazzaroni, Raffaello,Salvadori, Piero
, p. 41 - 46 (1995)
The hydroformylation of 1,3-butadiene, 2-methyl-1,3-butadiene and 1,3-pentadiene using rhodium vapour-mesitylene cocondesates as a catalytic precursor is reported.The reaction gives β,γ-unsaturated monoaldehydes with high chemoselectivity and regioselectivity. η3-Butenyl complexes, derived from the addition of Rh-H species to the conjugated double-bound system, are likely to be intermediates, as suggested by deuterioformylation experiments. Keywords: Rhodium vapour; Hydroformylation; Conjugated dienes; Catalysis; Unsaturated aldehydes
Gold(I)-catalyzed intramolecular [4+3]-cycloaddition reactions with furan propargyl esters as the substrates: Carbenoid vsstabilized allyl cation
Gung, Benjamin W.,Conyers, Ryan C.,Wonser, Josh
, p. 1238 - 1242 (2013)
The tricyclic ring system with an oxabicyclo[3.2.1]octadiene and a fused six-membered ring was produced efficiently using the readily available propargyl ester furan substrate in the presence of a Au(I) complex. The reaction involves a tandem 3,3-rearrangement of the propargyl ester followed by an intramolecular [4+3]-cycloaddition reaction. Both the primary ligand of the gold complex (N-heterocyclic carbene; NHC) and a neutral dynamic ligand (PhCN) are important for the success of the reaction. Georg Thieme Verlag Stuttgart. New York.
Mok
, p. 1432 (1970)
Photoinduced Palladium-Catalyzed Dicarbofunctionalization of Terminal Alkynes
Yang, Zhen,Koenigs, Rene M.
supporting information, p. 3694 - 3699 (2021/02/01)
Herein, a conceptually distinct approach was developed that allowed for the dicarbofunctionalization of alkynes at room temperature using simple, bench-stable alkyl iodides and a second molecule of alkyne as coupling partner. Specifically, the photochemical activation of palladium complexes enabled this strategic dicarbofunctionalization via addition of alkyl radicals from secondary and tertiary alkyl iodides and formation of an intermediate palladium vinyl complex that could undergo subsequent Sonogashira reaction with a second alkyne molecule. This alkylation–alkynylation sequence allowed the one-step synthesis of 1,3-enynes including heteroarenes and biologically active compounds with high efficiency without exogenous photosensitizers or oxidants and now opens up pathways towards cascade reactions via photochemical palladium catalysis.
Butadiene hydroformylation to adipaldehyde with Rh-based catalysts: Insights into ligand effects
Yu, Si-min,Snavely, William K.,Chaudhari, Raghunath V.,Subramaniam, Bala
, (2019/12/24)
Rh-catalyzed hydroformylation of butadiene to adipaldehyde is a promising alternative route for producing valuable C6 compounds such as adipic acid and hexamethylenediamine. Fundamental insights into reaction pathways, aimed at enhancing adipaldehyde yield, were obtained from temporal concentration profiles and in situ ReactIR studies of butadiene hydroformylation on Rh complexes at 80 °C and 14 bar syngas (molar CO/H2 = 1) pressure in a batch reactor. Specifically, the effects of operating conditions and eight commercially available ligands on activity and selectivity were systematically investigated. It was found that the adipaldehyde selectivity is independent of the ligand/Rh ratio, rhodium concentration, butadiene concentration and syngas pressure, but significantly dependent on the type of ligand used. For example, while the DIOP ligand provided an adipaldehyde yield of ～40% with butadiene as a substrate, the 6-DPPon ligand gave a maximum adipaldehyde yield of ～93% with 4-pentenal as substrate. Furthermore, the adipaldehyde selectivity correlates well with the natural bite angle of the various ligands. ReactIR studies suggest that the preferential formation of the stable rhodium η3-crotyl complex with the various Rh complexes may be the main reason for the low adipaldehyde selectivity.
Nickel-Catalyzed Selective Reduction of Carboxylic Acids to Aldehydes
Iosub, Andrei V.,Morav?ík, ?tefan,Wallentin, Carl-Johan,Bergman, Joakim
supporting information, p. 7804 - 7808 (2019/10/14)
The direct reduction of carboxylic acids to aldehydes is a fundamental transformation in organic synthesis. The combination of an air-stable Ni precatalyst, dimethyl dicarbonate as an activator, and silane reductant effects this reduction for a wide variety of substrates, including pharmaceutically relevant structures, in good yields and with no overreduction to alcohols. Moreover, this methodology is scalable, allows access to deuterated aldehydes, and is also compatible with one-pot utilization of the aldehyde products.
