69573-51-9Relevant academic research and scientific papers
Reductive C-C Coupling by Desulfurizing Gold-Catalyzed Photoreactions
Zhang, Lumin,Si, Xiaojia,Yang, Yangyang,Witzel, Sina,Sekine, Kohei,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
, p. 6118 - 6123 (2019/07/03)
[Au2(μ-dppm)2]Cl2-mediated photocatalysis reactions are usually initiated by ultraviolet A (UVA) light; herein, an unreported system using blue light-emitting diodes (LEDs) as excitation light source was found. The red shift of the absorption wavelength originates from the combination of [Au2(μ-dppm)2]Cl2 and ligand (Ph3P or mercaptan). On the basis of this finding, a gold-catalyzed reductive desulfurizing C-C coupling of electrophilic radicals and styrenes mediated by blue LEDs is presented, a coupling which cannot be efficiently accessed by previously reported methods. This mild and highly efficient C-C bond formation strategy uses mercaptans both as electron-deficient alkyl radical precursor as well as the hydrogen source. Two examples of amino acids have also been modified by using this strategy. Moreover, this methodology could be applied in polymer synthesis. Gram-scale synthesis and mechanistic insights into this transformation are also presented.
Parameters Influencing Reactivity and Regioselectivity in the Methoxycarbonylation of Arylalkenes
Du Plessis, Maretha,Marais, Charlene,Bezuidenhoudt, Barend C. B.
, p. 557 - 565 (2016/02/14)
Previous research showed that the steric bulk, electronic character, and bite angle of the ligand have an influence on both the catalyst activity and regioselectivity of hydroformylation and hydroesterification reactions. However, little is known in this regard about the influence of the steric and electronic environment around the double bond of the substrate. A variety of arylalkenes were therefore subjected to methoxycarbonylation to investigate the steric and electronic effects of substituents on the aromatic ring of the substrate on the regioselectivity and reactivity in the methoxycarbonylation reaction of these substrates with a Pd(II)/Al(OTf)3/Ph3P catalyst system.
Synthesis of four stereoisomers of (S)-2-methylpent-3-yl 3,13-dimethylpentadecanoate, a sex pheromone of the bagworm moth clania variegate, using stereospecific inversion of secondary sulfonates as a key step
Taguri, Tomonori,Yamamoto, Masanobu,Fujii, Toru,Muraki, Yuta,Ando, Tetsu
, p. 6924 - 6933 (2013/11/06)
Females of some lepidopteran species produce novel sex pheromones with a methyl-branched structure, such as 2-methylpent-3-yl 3,13-dimethylpentadecanoate secreted by the bagworm moth Clania variegate. Recently, we have established a simple preparative method for the synthesis of methyl-branched building blocks by utilizing an SN2 reaction of chiral secondary tosylates derived from (S)- and (R)-propylene oxides. The usefulness of these building blocks was demonstrated by their application in the synthesis of all four stereoisomers of an acid moiety in the bagworm pheromone. The enantiomeric purities of all building blocks were confirmed by enantioselective HPLC analysis. We found that a secondary mesylate was superior to the corresponding tosylate because it avoided an elimination side reaction, and racemization in the SN2 reaction was not observed even at high temperature (150 °C). Finally, each optically active acid was esterified with (S)-2-methyl-3-pentanol, which was synthesized by a new route starting from (S)-valine. A simple route to methyl-branched building blocks has been developed by utilizing an S N2 reaction of chiral secondary sulfonates derived from (S)- and (R)-propylene oxides. The usefulness of these building blocks was demonstrated by the stereospecific synthesis of all four stereoisomers of a bagworm pheromone. Copyright
Highly efficient copper(I) iodide-tolyl-BINAP-catalyzed asymmetric conjugate addition of methylmagnesium bromide to α,β-unsaturated esters
Wang, Shun-Yi,Lum, Tze-Keong,Ji, Shun-Jun,Loh, Teck-Peng
supporting information; experimental part, p. 673 - 677 (2009/04/10)
A highly efficient asymmetric conjugate addition of methylmagnesium bromide (MeMgBr) to α,β-unsaturated esters catalyzed by copper(I) iodide-tolyl-BNIP (CuI-Tol-BINAP) is described.
C-C Bond Formation via Carbon-Centered Radicals Generated from Dicarbonyl(η5-cyclopentadienyl)organoiron Complexes
Giese, Bernd,Gebhard, Thoma
, p. 1143 - 1155 (2007/10/02)
Irradiation of benzyldicarbonyl(η5-cyclopentadienyl)iron complex (2) leads to homolytic cleavage of the Fe-C bond.In the presence of activated alkenes, radical addition occurs, and both saturated and unsaturated addition products 7-9 are formed.Photolysis of alkyliron complexes 2, 3, and 20 in the presence of acrylonitrile leads to the same products as the irradiation of the respective acyliron complexes 28-30.This indicates that, under photolytical conditions, alkyl and acyl complexes are in equilibrium with each other.
Catalytic Hydrogenolysis of Methyl 2-Siloxycyclopropanecarboxylates: Investigations Regarding Chemoselectivity, Regioselectivity, and Stereoselectivity
Brueckner, Christiane,Reissig, Hans-Ulrich
, p. 617 - 626 (2007/10/02)
Alkyl-substituted methyl 2-(trimethylsiloxy)cyclopropanecarboxylates 8a - 8f are opened by hydrogen in the presence of palladium on carbon affording 4-oxoalkanoic esters 10a - 10e by desilylation. 2-Phenyl-substituted cyclopropanes 8g - 8j, however, provide 4-phenylbutanoic esters 13g - 13j under these conditions.Formation of 13j is not stereoselective.Here the primary cyclopropane cleavage is followed by hydrogenolysis of the benzylic C-O bond.This subsequent reaction can be suppressed in the case of 8g by poisoning the catalyst with triethylamine; otherwise the tert-butyldimethylsiloxy compounds 11g - 11i have to be used.Butanoic esters 14h and 14i, respectively, are formed as mixtures of diastereomeres, which is another indication for nonstereoselective hydrogenolysis of cyclopropanes.Whereas slow desilylation by hydrogen was observed with the 3-phenyl-substituted cyclopropane derivative 8k, the vinylcyclopropane 8m in part suffers cleavage of the 1-3 bond of the three-membered ring.Regio- and stereoselectivity of the hydrogenolysis of the donor-acceptor-substituted cyclopropanes 8 and 11 are discussed.
