- Ag/P-Stereogenic Phosphine-Catalyzed Enantioselective 1,3-Dipolar Cycloadditions: A Method to Optically Active Pyrrolidines
-
A Ag/P-stereogenic phosphine-complex-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with electron-deficient olefins is reported. In this reaction, highly functionalized pyrrolines with a spiro-quaternary stereogenic center were obtained in good yields (up to 99%) with excellent levels of diastereo-(up to >20:1 dr) and enantioselectivities (up to >99% ee). The chirality of adducts was controlled predominantly by the P-stereogenic phosphines.
- Zhi, Mengna,Gan, Zhenjie,Ma, Rong,Cui, Hao,Li, Er-Qing,Duan, Zheng,Mathey, Fran?ois
-
supporting information
(2019/05/07)
-
- Synthesis of high-density aviation fuels with methyl benzaldehyde and cyclohexanone
-
A new two-step process was developed for the synthesis of high-density jet fuel range tricyclic alkanes with methyl benzaldehydes and cyclohexanone which can be derived from lignocellulose. In the first step, C14 oxygenates (i.e. 2-(2-methylbenzylidene)cyclohexanone or 2-(4-methylbenzylidene)cyclohexanone) were obtained by the solvent-free aldol condensation of 2-methyl benzaldehyde (or 4-methyl benzaldehyde) and cyclohexanone. Among the investigated catalysts, the EAOAc ionic liquid (a renewable catalyst which was prepared with ethanolamine and acetic acid) exhibited the highest activity and good stability for this reaction. Over it, high carbon yields (~85%) of C14 oxygenates were achieved under mild reaction conditions (353 K, 6 h). In the second step, the C14 oxygenates were selectively converted into 1-methyldodecahydro-1H-fluorene and 3-methyldodecahydro-1H-fluorene by the aqueous phase hydrodeoxygenation (APHDO) over a commercial Pd/C catalyst. According to our measurement, the 1-methyldodecahydro-1H-fluorene and 3-methyldodecahydro-1H-fluorene as obtained have high densities (0.99 g mL-1 and 0.96 g mL-1, respectively, at 298 K). As a potential application, they can be used as additives to improve the volumetric heat values of the current bio-jet fuels.
- Xu, Jilei,Li, Ning,Li, Guangyi,Han, Fengan,Wang, Aiqin,Cong, Yu,Wang, Xiaodong,Zhang, Tao
-
supporting information
p. 3753 - 3760
(2018/08/22)
-
- Chiral Cyclohexyl-Fused Spirobiindanes: Practical Synthesis, Ligand Development, and Asymmetric Catalysis
-
1,1′-Spirobiindane has been one type of privileged skeleton for chiral ligand design, and 1,1′-spirobiindane-based chiral ligands have demonstrated outstanding performance in various asymmetric catalysis. However, the access to enantiopure spirobiindane is quite tedious, which obstructs its practical application. In the present article, a facile enantioselective synthesis of cyclohexyl-fused chiral spirobiindanes has been accomplished, in high yields and excellent stereoselectivities (up to >99% ee), via a sequence of Ir-catalyzed asymmetric hydrogenation of α,α′-bis(arylidene)ketones and TiCl4 promoted asymmetric spiroannulation of the hydrogenated chiral ketones. The protocol can be performed in one pot and is readily scalable, and has been utilized in a 25 g scale asymmetric synthesis of cyclohexyl-fused spirobiindanediol (1S,2S,2′S)-5, in >99% ee and 67% overall yield for four steps without chromatographic purification. Facile derivations of (1S,2S,2′S)-5 provided straightforward access to chiral monodentate phosphoramidites 6a-c and a tridentate phosphorus-amidopyridine 11, which were evaluated as chiral ligands in several benchmark enantioselective reactions (hydrogenation, hydroacylation, and [2 + 2] reaction) catalyzed by transition metal (Rh, Au, or Ir). Preliminary results from comparative studies showcased the excellent catalytic performances of these ligands, with a competency essentially equal to the corresponding well-established privileged ligands bearing a regular spirobiindane backbone. X-ray crystallography revealed a close resemblance between the structures of the precatalysts 20 and 21 and their analogues, which ultimately help to rationalize the almost identical stereochemical outcomes of reactions catalyzed by metal complexes of spirobiindane-derived ligands with or without a fused cyclohexyl ring on the backbone. This work is expected to stimulate further applications of this type of readily accessible skeletons in development of chiral ligands and functional molecules.
- Zheng, Zhiyao,Cao, Yuxi,Chong, Qinglei,Han, Zhaobin,Ding, Jiaming,Luo, Chenguang,Wang, Zheng,Zhu, Dongsheng,Zhou, Qi-Lin,Ding, Kuiling
-
supporting information
p. 10374 - 10381
(2018/08/03)
-
- Inhibitor of CBP histone acetyltransferase downregulates p53 activation and facilitates methylation at lysine 27 on histone H3
-
Tumor suppressor p53-directed apoptosis triggers loss of normal cells, which contributes to the side-effects from anticancer therapies. Thus, small molecules with potential to downregulate the activation of p53 could minimize pathology emerging from anticancer therapies. Acetylation of p53 by the histone acetyltransferase (HAT) domain is the hallmark of coactivator CREB-binding protein (CBP) epigenetic function. During genotoxic stress, CBP HAT-mediated acetylation is essential for the activation of p53 to transcriptionally govern target genes, which control cellular responses. Here, we present a small molecule, NiCur, which blocks CBP HAT activity and downregulates p53 activation upon genotoxic stress. Computational modeling reveals that NiCur docks into the active site of CBP HAT. On CDKN1A promoter, the recruitment of p53 as well as RNA Polymerase II and levels of acetylation on histone H3 were diminished by NiCur. Specifically, NiCur reduces the levels of acetylation at lysine 27 on histone H3, which concomitantly increases the levels of trimethylation at lysine 27. Finally, NiCur attenuates p53-directed apoptosis by inhibiting the Caspase 3 activity and cleavage of Poly (ADP-ribose) polymerase (PARP) in normal gastrointestinal epithelial cells. Collectively, NiCur demonstrates the potential to reprogram the chromatin landscape and modulate biological outcomes of CBP-mediated acetylation under normal and disease conditions.
- Vincek, Adam S.,Patel, Jigneshkumar,Jaganathan, Anbalagan,Green, Antonia,Pierre-Louis, Valerie,Arora, Vimal,Rehmann, Jill,Mezei, Mihaly,Zhou, Ming-Ming,Ohlmeyer, Michael,Mujtaba, Shiraz
-
-
- Base-catalyzed cross coupling of secondary alcohols and aryl-aldehydes with concomitant oxidation of alcohols to ketones: An alternative route for synthesis of the Claisen-Schmidt condensation products
-
Base-catalyzed C–C cross coupling of secondary alcohols and aryl-aldehydes was achieved, when an alcoholic solution of an aryl-aldehyde was stirred under reflux for 45?h in the presence of a catalytic (20?mol%) amount of K2CO3. The consistent formation of α,α′-bis-(benzylidene) alkanones was obtained in moderate to good yields using various secondary alcohols and substituted aryl-aldehydes. Herein, α,α′-bis-(benzylidene)alkanones, which are the classical products of Claisen-Schmidt (cross aldol) condensation, have been synthesized via an alternative strategy using secondary alcohols. Bis-(benzylidene) alkanones are an integral part of various drug regimes and the production of bis-(benzylidene) alkanones without using any precious metal is a major outcome of the present reaction.
- Satrawala, Naveen,Sharma, Kamal N.,Matsinha, Leah C.,Maqeda, Latisa,Siangwata, Shepherd,Smith, Gregory S.,Joshi, Raj K.
-
supporting information
p. 2761 - 2764
(2017/06/23)
-
- Chiral spirodihydroindene skeleton compound and preparation method thereof
-
The invention discloses a chiral spirodihydroindene skeleton compound and a preparation method thereof. The chiral spirodihydroindene skeleton compound is represented by formula I or I'. The preparation method of the chiral spirodihydroindene skeleton compound is characterized in that an intramolecular Friedel-Crafts reaction of a compound represented by formula III is carried out in a solvent under the action of a catalyst to prepare the compound represented by formula I, and the catalyst is a Bronsted acid or a Lewis acid. The preparation method has the advantages of no chiral initial raw material or chiral resolution reagent, no chiral resolution steps, simplicity, simplicity in post-treatment, good economic property, environmental protection, high product yield, and realization of high optical purity and high chemical purity of the product. Transition metal catalyzed asymmetric reaction catalysts prepared by adopting the chiral spirodihydroindene skeleton compound have a substantial catalysis effect, the product yield is greater than 99%, and the ee value of the product higher than 99%.
- -
-
Paragraph 0116-0119; 0121-0122
(2017/02/28)
-
- 2-Aminoalkyl-3,3a,4,5,6,7-hexahydro-3-phenyl-7(phenylmethylene)-2H-indazoles
-
Compounds of the following formula and their acid addition and quaternary salts and N-oxides SPC1 Wherein X is hydrogen, chloro, fluoro, trifluoromethyl, lower alkyl, or lower alkoxy, R is hydrogen or lower alkyl, A is alkylene of 1 to 8 carbons, and B is --NH2, EQU1 wherein R1 is lower alkyl and R2 is phenyl or phenyl-lower alkyl are disclosed. These compounds are useful as central nervous system depressants.
- -
-
-