87720-90-9Relevant articles and documents
Structure-Guided Regulation in the Enantioselectivity of an Epoxide Hydrolase to Produce Enantiomeric Monosubstituted Epoxides and Vicinal Diols via Kinetic Resolution
Hou, Xiao-Dong,Hu, Bo-Chun,Hu, Die,Lei, Yu-Qing,Rao, Yi-Jian,Wu, Min-Chen,Zhang, Dong
supporting information, p. 1757 - 1761 (2022/03/16)
Structure-guided microtuning of an Aspergillus usamii epoxide hydrolase was executed. One mutant, A214C/A250I, displayed a 12.6-fold enhanced enantiomeric ratio (E = 202) toward rac-styrene oxide, achieving its nearly perfect kinetic resolution at 0.8 M in pure water or 1.6 M in n-hexanol/water. Several other beneficial mutants also displayed significantly improved E values, offering promising biocatalysts to access 19 structurally diverse chiral monosubstituted epoxides (97.1 - ≥ 99% ees) and vicinal diols (56.2-98.0% eep) with high yields.
Site-Selective Mono-Oxidation of 1,2-Bis(boronates)
Yan, Lu,Morken, James P.
supporting information, p. 3760 - 3763 (2019/05/24)
Site-selective oxidation of vicinal bis(boronates) is accomplished through the use of trimethylamine N-oxide in 1-butanol solvent. The reaction occurs with good efficiency and selectivity across a range of substrates, providing 2-hydro-1-boronic esters which are shown to be versatile intermediates in the synthesis of chiral building blocks.
Raw and waste plant materials as sources of fungi with epoxide hydrolase activity. Application to the kinetic resolution of aryl and alkyl glycidyl ethers
Dolcet, Marta,Torres, Mercè,Canela-Garayoa, Ramon
, p. 78 - 88 (2017/09/30)
The by-products of olive oil production can be used as sources of microbial strains. Penicillium sp., Aspergillus terreus, Penicillium aurantiogriseum, Aspergillus tubingensis and Aspergillus niger were selected on the basis of their epoxide-hydrolyzing activity towards racemic rac-glycidyl phenyl ether. We studied the effect on enzymatic activity of adding styrene oxide to the growth medium. It induced the biosynthesis of epoxide hydrolases and reduced cell growth. The resolution capacity of the five fungi was tested on rac-glycidyl phenyl ether, rac-benzyl glycidyl ether, rac-1,2-epoxyhexane and rac-1,2-epoxyoctane. The resolution of rac-glycidyl phenyl ether by A. niger, rac-benzyl glycidyl ether by P. aurantiogriseum and A. terreus, rac-1,2-epoxyhexane by A. tubingensis and rac-1,2-epoxyoctane by A. terreus provided (S)-3-phenoxy-1,2-propanediol (45.1% yield, 51.4% ee), (R)-3-benzyloxy-1,2-propanediol (40.8% yield, 43.3% ee), (S)-3-benzyloxy-1,2-propanediol (45.4% yield, 45.6% ee), (R)-1,2-hexanediol (70.4% yield, 24.4% ee) and (R)-1,2-octanediol (21.4% yield, 27.5% ee), respectively. The (R)-enantiopreference of the epoxide hydrolases from P. aurantiogriseum is unprecedented.
Carbohydrate/DBU Cocatalyzed Alkene Diboration: Mechanistic Insight Provides Enhanced Catalytic Efficiency and Substrate Scope
Yan, Lu,Meng, Yan,Haeffner, Fredrik,Leon, Robert M.,Crockett, Michael P.,Morken, James P.
supporting information, p. 3663 - 3673 (2018/03/21)
A mechanistic investigation of the carbohydrate/DBU cocatalyzed enantioselective diboration of alkenes is presented. These studies provide an understanding of the origin of stereoselectivity and also reveal a strategy for enhancing reactivity and broadening the substrate scope.
Highly Enantioselective Iron-Catalyzed cis-Dihydroxylation of Alkenes with Hydrogen Peroxide Oxidant via an FeIII-OOH Reactive Intermediate
Zang, Chao,Liu, Yungen,Xu, Zhen-Jiang,Tse, Chun-Wai,Guan, Xiangguo,Wei, Jinhu,Huang, Jie-Sheng,Che, Chi-Ming
supporting information, p. 10253 - 10257 (2016/08/24)
The development of environmentally benign catalysts for highly enantioselective asymmetric cis-dihydroxylation (AD) of alkenes with broad substrate scope remains a challenge. By employing [FeII(L)(OTf)2] (L=N,N′-dimethyl-N,N′-bis(2-methyl-8-quinolyl)-cyclohexane-1,2-diamine) as a catalyst, cis-diols in up to 99.8 % ee with 85 % isolated yield have been achieved in AD of alkenes with H2O2as an oxidant and alkenes in a limiting amount. This “[FeII(L)(OTf)2]+H2O2” method is applicable to both (E)-alkenes and terminal alkenes (24 examples >80 % ee, up to 1 g scale). Mechanistic studies, including18O-labeling, UV/Vis, EPR, ESI-MS analyses, and DFT calculations lend evidence for the involvement of chiral FeIII-OOH active species in enantioselective formation of the two C?O bonds.
Carbohydrate-Catalyzed Enantioselective Alkene Diboration: Enhanced Reactivity of 1,2-Bonded Diboron Complexes
Fang, Lichao,Yan, Lu,Haeffner, Fredrik,Morken, James P.
supporting information, p. 2508 - 2511 (2016/03/12)
Catalytic enantioselective diboration of alkenes is accomplished with readily available carbohydrate-derived catalysts. Mechanistic experiments suggest the intermediacy of 1,2-bonded diboronates.
Total synthesis of the salicyldehydroproline-containing antibiotic promysalin
Kaduskar, Rahul D.,Dhavan, Atul A.,Dallavalle, Sabrina,Scaglioni, Leonardo,Musso, Loana
, p. 2034 - 2041 (2016/04/05)
A convergent total synthesis of promysalin, a metabolite of Pseudomonas putida RW10S1 with antibiotic activity, is described. The synthetic approach is based around a salicyldehydroproline core and a dihydroxymyristamide fragment. Crucial steps include a MacMillan asymmetric α-hydroxylation applied for the construction of the myristamide framework, and a lactam reduction by Superhydride to obtain the dehydroproline fragment. Because of the modular nature of the synthesis, ready access to analogues for biological evaluation is available.
Lipase-catalyzed stereoresolution of long-chain 1,2-alkanediols: A screening of preferable reaction conditions
Parve, Jaan,Reile, Indrek,Aid, Tiina,Kudrja?ova, Marina,Müürisepp, Aleksander-Mati,Vallikivi, Imre,Villo, Ly,Aav, Riina,Pehk, T?nis,Vares, Lauri,Parve, Omar
, p. 60 - 69 (2015/04/14)
Scalable lipase-catalytic method for the kinetic resolution of long-chain 1,2-alkanediol enantiomers via stereoselective cleavage of esters was developed. The influence of lipase, reaction medium, nucleophile, temperature and the structure of the acyl group on the reaction velocity, the stereopreference and the stereoselectivity of the deacylation was studied. In addition, the rate of the spontaneous intramolecular migration of different acyl groups was determined for the intermediate 2-monoesters. The acyl group migration may diminish the apparent stereoselectivity of the two-step process if fast migrating acyl groups are used. It was found that the migration rate of different acyl groups differs by up to two orders of magnitude, being faster for acetyl and isobutyryl and much slower for butyryl and benzoyl groups. The best results were obtained by the sequential methanolysis of bis-butyryl-1,2-alkanediols in an acetonitrile/methanol mixture catalyzed by Candida antarctica lipase B (CALB) at 20 °C, affording (S)-1,2-alkanediols. Stereo- and chemoselective crystallization of the deacylated (S)-1,2-alkanediols from the reaction mixture complements the enzymatic process improving the stereochemical purity to up to ee > 99.8%. (R)-1,2-Alkanediol 2-monoesters were separated from the mother liquor and enriched stereochemically by repeated incubation with CALB, then separated, hydrolyzed with alkali and crystallized to afford (R)-alkanediols of ee > 99.8%.
Asymmetric hydrolytic kinetic resolution with recyclable polymeric Co(iii)-salen complexes: A practical strategy in the preparation of (S)-metoprolol, (S)-toliprolol and (S)-alprenolol: Computational rationale for enantioselectivity
Roy, Tamal,Barik, Sunirmal,Kumar, Manish,Kureshy, Rukhsana I.,Ganguly, Bishwajit,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
, p. 3899 - 3908 (2015/02/19)
A series of chiral polymeric Co(iii)-salen complexes based on a number of achiral and chiral linkers were synthesized and their catalytic performances were assessed in the asymmetric hydrolytic kinetic resolution of terminal epoxides. The effects of the linker were judiciously studied and it was found that in the case of the chiral BINOL-based polymeric salen complex 1, there was an enrichment in catalyst reactivity and enantioselectivity of the unreacted epoxide, particularly in the case of short as well as long chain aliphatic epoxides. Good isolated yields of the unreacted epoxide (up to 46% compared to 50% theoretical yield) along with high enantioselectivity (up to 99%) were obtained in most cases using catalyst 1. Further studies showed that catalyst 1 could retain its catalytic activity for six cycles under the present reaction conditions without any significant loss in activity or enantioselectivity. To show the practical applicability of the above synthesized catalyst we have synthesised some potent chiral β-blockers in moderate yield and high enantioselectivity using complex 1. The DFT (M06-L/6-31+G??//ONIOM(B3LYP/6-31G?:STO-3G)) calculations revealed that the chiral BINOL linker influences the enantioselectivity achieved with Co(iii)-salen complexes. Further, the transition state calculations show that the R-BINOL linker with the (S,S)-Co(iii)-salen complex is energetically preferred over the corresponding S-BINOL linker with the (S,S)-Co(iii)-salen complex for the HKR of 1,2-epoxyhexane. The role of non-covalent C-H?π interactions and steric effects has been discussed to control the HKR reaction of 1,2-epoxyhexane.
Reactivity of an iron-oxygen oxidant generated upon oxidative decarboxylation of biomimetic iron(II) α-hydroxy acid complexes
Paria, Sayantan,Chatterjee, Sayanti,Paine, Tapan Kanti
supporting information, p. 2810 - 2821 (2014/04/03)
Three biomimetic iron(II) α-hydroxy acid complexes, [(Tp Ph2)FeII(mandelate)(H2O)] (1), [(Tp Ph2)FeII(benzilate)] (2), and [(TpPh2)Fe II(HMP)] (3), together with two iron(II) α-methoxy acid complexes, [(TpPh2)FeII(MPA)] (4) and [(Tp Ph2)FeII(MMP)] (5) (where HMP = 2-hydroxy-2- methylpropanoate, MPA = 2-methoxy-2-phenylacetate, and MMP = 2-methoxy-2-methylpropanoate), of a facial tridentate ligand TpPh2 [where TpPh2 = hydrotris(3,5-diphenylpyrazole-1-yl)borate] were isolated and characterized to study the mechanism of dioxygen activation at the iron(II) centers. Single-crystal X-ray structural analyses of 1, 2, and 5 were performed to assess the binding mode of an α-hydroxy/methoxy acid anion to the iron(II) center. While the iron(II) α-methoxy acid complexes are unreactive toward dioxygen, the iron(II) α-hydroxy acid complexes undergo oxidative decarboxylation, implying the importance of the hydroxyl group in the activation of dioxygen. In the reaction with dioxygen, the iron(II) α-hydroxy acid complexes form iron(III) phenolate complexes of a modified ligand (TpPh2*), where the ortho position of one of the phenyl rings of TpPh2 gets hydroxylated. The iron(II) mandelate complex (1), upon decarboxylation of mandelate, affords a mixture of benzaldehyde (67%), benzoic acid (20%), and benzyl alcohol (10%). On the other hand, complexes 2 and 3 react with dioxygen to form benzophenone and acetone, respectively. The intramolecular ligand hydroxylation gets inhibited in the presence of external intercepting agents. Reactions of 1 and 2 with dioxygen in the presence of an excess amount of alkenes result in the formation of the corresponding cis-diols in good yield. The incorporation of both oxygen atoms of dioxygen into the diol products is confirmed by 18O-labeling studies. On the basis of reactivity and mechanistic studies, the generation of a nucleophilic iron-oxygen intermediate upon decarboxylation of the coordinated α-hydroxy acids is proposed as the active oxidant. The novel iron-oxygen intermediate oxidizes various substrates like sulfide, fluorene, toluene, ethylbenzene, and benzaldehyde. The oxidant oxidizes benzaldehyde to benzoic acid and also participates in the Cannizzaro reaction.
