- Ylide-Functionalized Phosphine (YPhos)-Palladium Catalysts: Selective Monoarylation of Alkyl Ketones with Aryl Chlorides
-
Ylide-functionalized phosphine (YPhos) ligands allow the palladium-catalyzed α-arylation of alkyl ketones with aryl chlorides with record setting activity. Using a cyclohexyl-substituted YPhos ligand, a wide range of challenging ketone substrates was efficiently and selectively monoarylated under mild conditions. A newly designed YPhos ligand bearing tert-butyl groups on the coordinating phosphorus atom is already active at room temperature. The synthetic potential was demonstrated by gram-scale reactions and the succinct synthesis of ?-caprolactone derivatives.
- Hu, Xiao-Qiang,Lichte, Dominik,Rodstein, Ilja,Weber, Philip,Seitz, Ann-Katrin,Scherpf, Thorsten,Gessner, Viktoria H.,Goo?en, Lukas J.
-
supporting information
p. 7558 - 7562
(2019/10/02)
-
- Direct Asymmetric α-Hydroxylation of Cyclic α-Branched Ketones through Enol Catalysis
-
Enantiopure α-hydroxy carbonyl compounds are common scaffolds in natural products and pharmaceuticals. Although indirect approaches towards their synthesis are known, direct asymmetric methodologies are scarce. Herein, we report the first direct asymmetric α-hydroxylation of α-branched ketones through enol catalysis, enabling a facile access to valuable α-keto tertiary alcohols. The transformation, characterized by the use of nitrosobenzene as the oxidant and a new chiral phosphoric acid as the catalyst, delivers a good scope and excellent enantioselectivities.
- Shevchenko, Grigory A.,Pupo, Gabriele,List, Benjamin
-
supporting information
p. 49 - 53
(2019/01/04)
-
- Discovery of Orally Efficacious Tetrahydrobenzimidazoles as TGR5 Agonists for Type 2 Diabetes
-
We have discovered a novel series of tetrahydrobenzimidazoles 3 as TGR5 agonists. Initial structure-activity relationship studies with an assay that measured cAMP levels in murine enteroendocrine cells (STC-1 cells) led to the discovery of potent agonists with submicromolar EC50 values for mTGR5. Subsequent optimization through methylation of the 7-position of the core tetrahydrobenzimidazole ring resulted in the identification of potent agonists for both mTGR5 and hTGR5 (human enteroendocrine NCI-H716 cells). While the lead compounds displayed low to moderate exposure after oral dosing, they significantly reduced blood glucose levels in C57 BL/6 mice at 30 mg/kg and induced a 13-22% reduction in the area under the blood glucose curve (AUC)0-120 min in oral glucose tolerance tests (OGTT).
- Zhang, Xuqing,Wall, Mark,Sui, Zhihua,Kauffman, Jack,Hou, Cuifen,Chen, Cailin,Du, Fuyong,Kirchner, Thomas,Liang, Yin,Johnson, Dana L.,Murray, William V.,Demarest, Keith
-
supporting information
p. 560 - 565
(2017/05/17)
-
- Catalytic asymmetric synthesis of sterically hindered tertiary α-aryl ketones
-
The catalytic asymmetric synthesis of a series of tertiary α-aryl cyclopentanones and cyclohexanones has been accomplished via a Pd-catalyzed decarboxylative protonation of the corresponding α-aryl-β-keto allyl esters. Enantioselectivities of up to 92% ee and 74% ee were achieved for cyclopentanone and cyclohexanone substrates, respectively. The route described gives access to these important structural motifs in moderate to high levels of enantioselectivity. In particular, this is only the second direct approach for the preparation of tertiary α-aryl cyclopentanones. The synthetic approach allows for simple modification of the aryl group. Significantly, substrates containing sterically hindered aryl groups gave the highest levels of enantioselectivity, and these aryl groups were readily installed by a Pb-mediated arylation of a β-keto allyl ester.
- Doran, Robert,Guiry, Patrick J.
-
p. 9112 - 9124
(2014/12/11)
-
- Construction of a chiral quaternary carbon center by catalytic asymmetric alkylation of 2-arylcyclohexanones under phase-transfer conditions
-
In this paper, we present an asymmetric alkylation of modified 2-arylcyclohexanones that employs a novel chiral ammonium bromide as a phase-transfer catalyst and an achiral auxiliary as a controller to improve the enantioselectivity to afford optically enriched products having a chiral quaternary carbon center.
- Kano, Taichi,Hayashi, Yumi,Maruoka, Keiji
-
supporting information
p. 7134 - 7137
(2013/06/27)
-
- A boron-based synthesis of the natural product (+)-trans- dihydrolycoricidine
-
Diastereoselective diboration results in the highly selective 1,4-dihydroxylation of chiral cyclohexadienes (see scheme). Together with the catalytic enantioselective conjugate allylboration, the diene diboration facilitates the asymmetric synthesis of the cytotoxic agent (+)-trans- dihydrolycoricidine (1). pin=pinacol. Copyright
- Poe, Sarah L.,Morken, James P.
-
supporting information; experimental part
p. 4189 - 4192
(2011/06/20)
-
- A general and efficient strategy for 7-aryloctahydroindole and cis-3a-aryloctahydroindole alkaloids: Total syntheses of (±)-γ- lycorane and (±)-crinane
-
A general and efficient approach to both 7-aryloctahydroindole and cis-3a-aryloctahydroindole alkaloids has been developed. The key step involves Michael additions of the corresponding kinetics and thermodynamics lithium enolates of ketone 9 to the versat
- Gao, Shuanhu,Tu, Yong Qiang,Song, Zhenlei,Wang, Aixia,Fan, Xiaohui,Jiang, Yijun
-
p. 6523 - 6525
(2007/10/03)
-
- New method for the preparation of 2-aryl-and 2-heteroarylcyclohexanones. Synthesis of 6,7,8,9-tetrahydro-5H-1,3-dioxolo[4,5-b]carbazole
-
2-Aryl- and 2-heteroarylcyclohexanones were prepared through 1,4-addition of lithiated species to 1-nitro-1-cyclohexene followed by Nef reaction in good yields. As a synthetic application of this method, 6,7,8,9-tetrahydro-5H-1,3-dioxolo[4,5-b]carbazole was synthesized.
- Santos, Roberto P.,Lopes, Rosangela S. C.,Lopes, Claudio C.
-
p. 845 - 848
(2007/10/03)
-
- Asymmetric Reductive Amination of Cycloalkanones, VII: Asymmetric Synthesis of cis-1R,2R- and cis-1S,2S,-2-Arylcyclohexanamines
-
The asymmetric synthesis of cis-2-arylcyclohexanamines 4 by a three-step procedure is reported: condensation of racemic 2-arylcyclohexanones 1 with the chiral auxiliary R-(+)- or S-(-)-1-phenylethylamine, respectively, leads to a mixture of the imin isomers 2.Upon hydrogenation with Raney-Nickel just one secondary amin of type 3 is obtained, which is hydrogenolyzed to the optically active primary cis-2-arylcyclohexanamines 4.The relative configuration as well as the conformation were derived from 1H-NMR data.The absolute configuration of the highly enantiomericallypure compounds 4 was determined by CD spectra.
- Nachtsheim, Corina M.,Frahm, August W.
-
p. 187 - 197
(2007/10/02)
-