201012-68-2Relevant articles and documents
Synthesis of (+)-sorokinianin
Watanabe, Hidenori,Onoda, Takahiro,Kitahara, Takeshi,Mori, Kenji
, p. 6015 - 6018 (1997)
Sorokinianin (1), an inhibitor of barley germination, was synthesized in optically active form employing d-carvone as the only chiral source. The key steps are stereoselective intra- and intermolecular aldol reactions to construct the bicyclo[3.2.1]octane
Total synthesis of (+)-cassaine utilizing an anionic polycyclization strategy
Ravindar, Kontham,Caron, Pierre-Yves,Deslongchamps, Pierre
, p. 6270 - 6273 (2013)
A stereoselective total synthesis of (+)-cassaine (1) via an anionic polycyclization methodology is described. Commercially available (+)-carvone (5), the only chiral source, was used to fix the entire stereochemistry of the natural product. Anionic polyc
Diels-Alder route to norbornane derived vicinal phosphane/borane frustrated Lewis pairs for the metal-free catalytic hydrogenation of α, β-unsaturated ketones
W?lke, Christian,Daniliuc, Constantin G.,Kehr, Gerald,Erker, Gerhard
supporting information, (2019/08/26)
The [4+2] cycloaddition reaction of the (dimesitylphosphino)cyclopentadienes 5a,b with N-phenylmaleimide gave the norbornene derivative 9. Its reduction with LiAlH4 produced the N-phenylpyrrolidino-annulated system 10. Treatment with Piers' bor
Negatively Charged N-Heterocyclic Carbene-Stabilized Pd and Au Nanoparticles and Efficient Catalysis in Water
Ferry, Angélique,Schaepe, Kira,Tegeder, Patricia,Richter, Christian,Chepiga, Kathryn M.,Ravoo, Bart Jan,Glorius, Frank
, p. 5414 - 5420 (2015/09/15)
Herein we describe the synthesis of negatively charged N-heterocyclic carbene (NHC)-functionalized palladium and gold nanoparticles (NPs), which are stable in water for over 3 months. The formation of these NHC-NPs proceeds via an efficient ligand exchange procedure. This method was successfully applied to different negatively charged NHCs bearing sulfonate and carboxylate groups. The obtained PdNPs were investigated as catalysts in hydrogenation reactions and showed high catalytic activity (TON up to 2500 and TOF up to 2000 h-1).
Platinum Nanoparticles Stabilized by Glycerodendrimers: Synthesis and Application to the Hydrogenation of α,β-Unsaturated Ketones under Mild Conditions
Menot, Bérengère,Salmon, Lionel,Bouquillon, Sandrine
supporting information, p. 4518 - 4523 (2015/10/06)
Air-stable platinum nanoparticles stabilized by glycerodendrimers were prepared in water and analyzed by TEM. These platinum nanoparticles showed good catalytic activity for the reduction of α,β-unsaturated ketones to saturated ketones at room temperature in water or in water/THF (1:1) under H2 (101.3 kPa). The catalytic species was recovered and recycled several times.
Enzymatic hydrogenation of diverse activated alkenes. Identification of two Bacillus old yellow enzymes with broad substrate profiles
Zhang, Hailing,Gao, Xiuzhen,Ren, Jie,Feng, Jinhui,Zhang, Tongcun,Wu, Qiaqing,Zhu, Dunming
, p. 118 - 125 (2014/05/20)
By whole cell transformation, 32 out of 71 strains showed OYEs activity toward maleimide in the first round screening. Among them, a Bacillus strain was identified to be active toward a selection of substrates with different electron-withdrawing groups. Two OYE homologous genes, bac-oye1 and bac-oye2 were cloned from this strain and overexpressed in Escherichia coli BL21(DE3). The recombinant enzyme Bac-OYE2 showed a broader pH range (6.0-10.5), while Bac-OYE1 was so sensitive to pH that it lost most of the enzyme activity below pH 6.0 or above pH 9.0. The reaction temperature exerted similar effects on the activities of both enzymes, but the stability of Bac-OYE2 was more sensitive to the temperature than Bac-OYE1. In addition to α,β-unsaturated aldehydes, ketones, nitroalkenes, and the double activated carboxylic acids, esters, nitriles and cyclic imides, Bac-OYE1 and Bac-OYE2 also exhibited activities toward the "borderline" substrates such as unsaturated lactones, mono carboxylic esters, showing their broader substrate scopes. These enzymes also had excellent enantioselectivity as evidenced by the reductions of several α,β-unsaturated cyclic ketones, α-substituted α,β-unsaturated carboxylic esters and 2-methyl maleimide. For example, methyl 2-acetamidoacrylate was reduced by Bac-OYE1 with >99% conversion and >99% ee.
Pichia stipitis OYE 2.6 variants with improved catalytic efficiencies from site-saturation mutagenesis libraries
Patterson-Orazem, Athéna,Sullivan, Bradford,Stewart, Jon D.
, p. 5628 - 5632 (2015/01/09)
An earlier directed evolution project using alkene reductase OYE 2.6 from Pichia stipitis yielded 13 active site variants with improved properties toward three homologous Baylis-Hillman adducts. Here, we probed the generality of these improvements by testing the wild-type and all 13 variants against a panel of 16 structurally-diverse electron-deficient alkenes. Several substrates were sterically demanding, and as hoped, creating additional active site volume yielded better conversions for these alkenes. The most impressive improvement was found for 2-butylidenecyclohexanone. The wild-type provided less than 20% conversion after 24 h; a triple mutant afforded more than 60% conversion in the same time period. Moreover, even wild-type OYE 2.6 can reduce cyclohexenones with very bulky 4-substituents efficiently.
Versatile CuI/Pd0 dual catalysis for the synthesis of quaternary α-allylated carbonyl compounds: Development, mechanistic investigations and scope
Nahra, Fady,Mace, Yohan,Boreux, Arnaud,Billard, Francois,Riant, Olivier
, p. 10970 - 10981 (2014/09/17)
We report herein a versatile cooperative dual catalysis reaction based on a CuI/Pd0 system. Mechanistic investigation shows that every component plays a crucial role in determining the reaction outcome. The reaction is successfully extended to various substrates; such as α,β-unsaturated ketones, malonates and coumarins. The strategy tolerates different substitution patterns and affords good yields for each family of substrates.
Copper/palladium-catalyzed 1,4 reduction and asymmetric allylic alkylation of α,β-unsaturated ketones: Enantioselective dual catalysis
Nahra, Fady,Mace, Yohan,Lambin, Dominique,Riant, Olivier
supporting information, p. 3208 - 3212 (2013/04/23)
Cooperative efforts: The catalytic coupling of the two organometallic intermediates is possible through a Cu/Pd-based dual catalysis (see scheme; LG=leaving group), in which the CuI catalytic cycle generates catalytically the starting material
Catalytic hydrogenation with frustrated lewis pairs: Selectivity achieved by size-exclusion design of lewis acids
Eroes, Gabor,Nagy, Krisztina,Mehdi, Hasan,Papai, Imre,Nagy, Peter,Kiraly, Peter,Tarkanyi, Gabor,Soos, Tibor
scheme or table, p. 574 - 585 (2012/03/08)
Catalytic hydrogenation that utilizes frustrated Lewis pair (FLP) catalysts is a subject of growing interest because such catalysts offer a unique opportunity for the development of transition-metal-free hydrogenations. The aim of our recent efforts is to further increase the functional-group tolerance and chemoselectivity of FLP catalysts by means of size-exclusion catalyst design. Given that hydrogen molecule is the smallest molecule, our modified Lewis acids feature a highly shielded boron center that still allows the cleavage of the hydrogen but avoids undesirable FLP reactivity by simple physical constraint. As a result, greater latitude in substrate scope can be achieved, as exemplified by the chemoselective reduction of α,β-unsaturated imines, ketones, and quinolines. In addition to synthetic aspects, detailed NMR spectroscopic, DFT, and 2H isotopic labeling studies were performed to gain further mechanistic insight into FLP hydrogenation. Copyright
