40872-81-9Relevant academic research and scientific papers
Catalytic Dynamic Kinetic Resolutions in Tandem to Construct Two-Axis Terphenyl Atropisomers
Beleh, Omar M.,Miller, Edward,Toste, F. Dean,Miller, Scott J.
, p. 16461 - 16470 (2020/10/26)
The defined structure of molecules bearing multiple stereogenic axes is of increasing relevance to materials science, pharmaceuticals, and catalysis. However, catalytic enantioselective approaches to control multiple stereogenic axes remain synthetically challenging. We report the catalytic synthesis of two-axis terphenyl atropisomers, with complementary strategies to both chlorinated and brominated variants, formed with high diastereo-and enantioselectivity. The chemistry proceeds through a sequence of two distinct dynamic kinetic resolutions: first, an atroposelective ring opening of Bringmann-type lactones produces a product with one established axis of chirality, and second, a stereoselective arene halogenation delivers the product with the second axis of chirality established. In order to achieve these results, a class of Br?nsted basic guanidinylated peptides, which catalyze an efficient atroposelective chlorination, is reported for the first time. In addition, a complementary bromination is reported, which also establishes the second stereogenic axis. These bromo-terphenyls are accessible following the discovery that chiral anion phase transfer catalysis by C2-symmetric phosphoric acids allows catalyst control in the second stereochemistry-determining event. Accordingly, we established the fully catalyst-controlled stereodivergent synthesis of all possible chlorinated stereoisomers while also demonstrating diastereodivergence in the brominated variants, with significant levels of enantioselectivity in all cases.
Organocatalytic Enantioselective Selenosulfonylation of a C-C Double Bond to Form Two Stereogenic Centers in an Aqueous Medium
Chen, Zhili,Hu, Fangli,Huang, Shengli,Zhao, Zhengxing,Mao, Hui,Qin, Wenling
, p. 8100 - 8111 (2019/06/17)
Organocatalytic selenosulfonylation of the C-C double bond of α,β-unsaturated ketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled up to a decagram scale via a simple workup procedure.
An iron-catalyzed hydroalkylation reaction of α,β-unsaturated ketones with ethers
Lan, Yun,Fan, Pei,Liu, Xiao-Wei,Meng, Fei-Fan,Ahmad, Tanveer,Xu, Yun-He,Loh, Teck-Peng
supporting information, p. 12353 - 12356 (2017/11/20)
A general strategy for the hydroalkylation of vinyl ketones using ethers catalyzed by an iron catalyst is described. This catalytic method permits direct transformation of easily accessible and abundant precursors into highly substituted, structurally diverse and functionally concentrated products.
Synthesis of Z-alkenes from Rh(I)-catalyzed olefin isomerization of β,γ-unsaturated ketones
Zhuo, Lian-Gang,Yao, Zhong-Ke,Yu, Zhi-Xiang
, p. 4634 - 4637 (2013/10/08)
Developing olefin isomerization reactions to reach kinetically controlled Z-alkenes is challenging because formation of trans-alkenes is thermodynamically favored under the traditional catalytic conditions using acids, bases, or transition metals as the catalysts. A new synthesis of Z-alkenes from Rh(I)-catalyzed olefin isomerization of β,γ-unsaturated ketones to α,β-unsaturated ketones was developed, providing an easy and efficient way to access various Z-enones.
Gold meets rhodium: Tandem one-pot synthesis of β-disubstituted ketones via meyer-schuster rearrangement and asymmetric 1,4-addition
Hansmann, Max M.,Hashmi, A. Stephen K.,Lautens, Mark
supporting information, p. 3226 - 3229 (2013/07/26)
An asymmetric one-pot tandem Au/Rh-catalyzed synthesis of highly enantioenriched β-disubstituted ketones starting from racemic propargyl alcohols is disclosed. The compatibility of the two metal complexes (Au/Rh) and their orthogonal ligand systems (NHC/d
Decarboxylative allylation of glyoxylic acids with diallyl carbonate
Manjolinho, Filipe,Gruenberg, Matthias F.,Rodriguez, Nuria,Goossen, Lukas J.
supporting information; experimental part, p. 4680 - 4683 (2012/10/08)
A catalyst system consisting of Pd(PPh3)4 and P(pTol)3 was found to effectively promote the intermolecular decarboxylative coupling of α-oxocarboxylic acids with diallyl carbonate to give α,β-unsaturated ketones. The key advantage of the new reaction protocol is that preformation of the allyl esters is not required. The reaction is believed to proceed via phosphane-mediated decarboxylation of the α-oxocarboxylates, leading to acyl anion equivalents that are allylated within the coordination sphere of the palladium catalyst. Under the reaction conditions, the double bond then migrates into conjugation with the carbonyl group. Copyright
COBALT(II)CHLORIDE CATALYSED ACYLATION OF ANISOLE
Iqbal, Javed,Khan, M. A.,Nayyar, Naresh K.
, p. 5179 - 5182 (2007/10/02)
Cobalt(II)chloride catalysed acylation of anisole with variety of acid chlorides proceeds via an acyl radical to give p-acylated anisoles in good yields.
