3391-86-4Relevant articles and documents
A cascade aerobic epoxidation of alkenes over Au/CeO2 and Ti-mesoporous material by "in situ" formed peroxides
Aprile, Carmela,Corma, Avelino,Domine, Marcelo E.,Garcia, Hermenegildo,Mitchell, Chris
, p. 44 - 53 (2009)
The one-pot epoxidation of alkenes with O2 is performed with nano-particulated Au/CeO2 and Ti-MCM-41 silylated materials in the presence of a hydrocarbon and azobis-iso-butyronitrile (AIBN) as a promoter. This initiator is able to fo
Bovine liver acetone powder (BLAP) catalyzed synthesis of chiral C-8 allyl alcohols: An application of substrate specificity approach
Basavaiah,Bhaskar Raju
, p. 4137 - 4148 (1994)
(S)-Matsutake alcohol is synthesized by enzymatic hydrolysis in 92% optical purity using bovine liver acetone powder (BLAP). The principle of substrate specificity approach is applied to the synthesis of C-8 allyl alcohols in 46-93% enantiomeric purities using BLAP.
Reductive deprotection of silyl groups with Wilkinson's catalyst/catechol borane
Patel, Pranav,Chang, Chih-Tsung,Kang, Namin,Lee, Gue-Jae,Powell, William S.,Rokach, Joshua
, p. 5289 - 5292 (2007)
Traditionally silyl groups are deprotected with acids and fluorides. These methods are, however, less discriminating when multi-silyl groups are present in the same molecule, resulting in lower yields of the desired products. The manipulation of these functions during the total synthesis of natural products, for example, prostaglandins and isoprostanes, requires the selective protection and deprotection of these groups. We are reporting here on a mild, selective and efficient method for the reductive deprotection of silyl groups using Wilkinson's catalyst/catechol borane or catechol borane alone.
[Pd]-Catalyzedpara-selective allylation of phenols: access to 4-[(E)-3-aryl/alkylprop-2-enyl]phenols
Chinnabattigalla, Sreenivasulu,Choudhury, Aditya,Gedu, Satyanarayana
supporting information, p. 8259 - 8263 (2021/10/12)
4-[(E)-3-Arylprop-2-enyl]phenols are omnipresent scaffolds and constitute natural products and biologically significant compounds. Obtusastyrene and obtustyrene are two such phenolic-based natural products isolated fromDalbergia retusa. The development of strategies based on a site-selective allylation, particularly protecting group-free substrates and non-activated coupling agents, is indispensable in organic synthesis. Herein, we present a highly regioselective [Pd]-catalyzedpara-allylation of phenols using simple, inactivated allylic alcohols as allylating coupling partners. Notably, this strategy is successful in open-air and under mild reaction conditions. Besides, the efficacy of the present protocol was demonstrated by the direct synthesis of obtusastyrene and obtustyrene.
Pickering-Droplet-Derived MOF Microreactors for Continuous-Flow Biocatalysis with Size Selectivity
Liang, Linfeng,Shi, Hu,Tian, Danping,Wang, Jun-Hao,Xue, Nan,Yang, Hengquan,Zhang, Xiaoming
supporting information, p. 16641 - 16652 (2021/10/20)
Enzymatic microarchitectures with spatially controlled reactivity, engineered molecular sieving ability, favorable interior environment, and industrial productivity show great potential in synthetic protocellular systems and practical biotechnology, but their construction remains a significant challenge. Here, we proposed a Pickering emulsion interface-directed synthesis method to fabricate such a microreactor, in which a robust and defect-free MOF layer was grown around silica emulsifier stabilized droplet surfaces. The compartmentalized interior droplets can provide a biomimetic microenvironment to host free enzymes, while the outer MOF layer secludes active species from the surroundings and endows the microreactor with size-selective permeability. Impressively, the thus-designed enzymatic microreactor exhibited excellent size selectivity and long-term stability, as demonstrated by a 1000 h continuous-flow reaction, while affording completely equal enantioselectivities to the free enzyme counterpart. Moreover, the catalytic efficiency of such enzymatic microreactors was conveniently regulated through engineering of the type or thickness of the outer MOF layer or interior environments for the enzymes, highlighting their superior customized specialties. This study provides new opportunities in designing MOF-based artificial cellular microreactors for practical applications.
Concise, scalable and enantioselective total synthesis of prostaglandins
Zhang, Fuhao,Zeng, Jingwen,Gao, Mohan,Wang, Linzhou,Chen, Gen-Qiang,Lu, Yixin,Zhang, Xumu
, p. 692 - 697 (2021/06/01)
Prostaglandins are among the most important natural isolates owing to their broad range of bioactivities and unique structures. However, current methods for the synthesis of prostaglandins suffer from low yields and lengthy steps. Here, we report a practicability-oriented synthetic strategy for the enantioselective and divergent synthesis of prostaglandins. In this approach, the multiply substituted five-membered rings in prostaglandins were constructed via the key enyne cycloisomerization with excellent selectivity (>20:1 d.r., 98% e.e.). The crucial chiral centre on the scaffold of the prostaglandins was installed using the asymmetric hydrogenation method (up to 98% yield and 98% e.e.). From our versatile common intermediates, a series of prostaglandins and related drugs could be produced in two steps, and fluprostenol could be prepared on a 20-gram scale. [Figure not available: see fulltext.]
Visible-Light Photoredox-Catalyzed α-Regioselective Conjugate Addition of Allyl Groups to Activated Alkenes
Gontala, Arjun,Woo, Sang Kook
supporting information, p. 3223 - 3228 (2020/07/06)
The α-regioselective conjugate addition of allyl groups to activated alkenes is a poorly explored area of research. Herein, we report an α-adduct and (E)-isomer selective conjugate addition of allylsilanes to activated alkenes by visible-light photoredox catalysis. The reaction involves allylic radicals that can be generated from allylsilanes through a photoinduced single-electron transfer mechanism. (Figure presented.).
Palladium-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted: O-carboranes containing α,β-unsaturated carbonyls
Li, Jiaoyi,Lu, Jian,Tian, Song,Wang, Qian,Zhang, Chuyi,Zhang, Jianwei,Zhou, Ling
supporting information, p. 4723 - 4727 (2020/07/13)
With the help of a carboxylic acid directing group, Pd-catalyzed regioselective synthesis of B(4,5)-or B(4)-substituted o-carboranes containing α,β-unsaturated carbonyls has been reported. The-COOH, removed during the course of the reaction, is responsible for controlling the regioselectivity. The desired products could be obtained in moderate to good yields.
Chemoselective Oxidation of p-Methoxybenzyl Ethers by an Electronically Tuned Nitroxyl Radical Catalyst
Hamada, Shohei,Sugimoto, Koichi,Elboray, Elghareeb E.,Kawabata, Takeo,Furuta, Takumi
supporting information, p. 5486 - 5490 (2020/07/24)
The oxidation of p-methoxy benzyl (PMB) ethers was achieved using nitroxyl radical catalyst 1, which contains electron-withdrawing ester groups adjacent to the nitroxyl group. The oxidative deprotection of the PMB moieties on the hydroxy groups was observed upon treatment of 1 with 1 equiv of the co-oxidant phenyl iodonium bis(trifluoroacetate) (PIFA). The corresponding carbonyl compounds were obtained by treating the PMB-protected alcohols with 1 and an excess of PIFA.
Effects of a forming process on the properties and structure of RANEY-Ni catalysts for the hydrogenation of 1,4-butenediol
Fan, Xing,Gao, Xianlong,Ma, Fengyun,Mo, Wenlong,Noritatsu, Tsubaki,Wu, Hongli
, p. 5516 - 5524 (2020/02/22)
Three commercial Ni-Al alloys formed by a vacuum atomization method (NAV), atmospheric atomization method (NAA) and high-temperature melting method (NAH) were leached by 10 wt% NaOH solution to prepare three RANEY-Ni catalysts (RNAV, RNAA and RNAH, correspondingly). The effects of a forming process on the structure of Ni-Al alloys and the corresponding RANEY-Ni catalysts were investigated via XRD, XPS, SEM, TEM, NH3-TPD, N2 adsorption-desorption and EDX-mapping studies. Also, the as-prepared RANEY-Ni catalysts were evaluated via the hydrogenation of 1,4-butenediol (BED) to produce 1,4-butanediol (BDO). The results showed that the specific surface areas and surface morphologies of the Ni-Al alloys present significant differences. Meanwhile, the RNAA sample presented a comparatively regular morphology, similar to a small piece of sugar cane. The weak and medium acid peak areas of the RNAA catalyst were lower than those of the other samples. RNAV showed higher weak and medium acid peak areas, demonstrating the higher number of acid centers on the surface of the catalyst. The surface of the RNAA catalyst obtained from NAA contained more active component-Ni, about 90 wt% on the surface, and the specific surface area of the sample was 75 times that of its precursor Ni-Al alloy powder (NAA). The evaluation results present that the RNAA catalyst shows better hydrogenation performance, with BED conversion of 100%, both BDO selectivity and yield of 46.11%.
