30959-91-2Relevant academic research and scientific papers
A SIMPLE, STEREOCONTROLLED SYNTHESIS OF α-ALKYLIDENE-γ-BUTYROLACTONES
Tanaka, Kazuhiko,Tamura, Norikazu,Kaji, Aritsune
, p. 595 - 598 (1980)
Treatment of γ-butyrolactone with bisdisulfide in the presence of 2.2 equivalents of lithium diisopropylamide followed by the addition of aldehydes gave predominantly (E)-α-alkylidene-γ-butyrolactones.In contrast, when the reaction
Reaction of N-heterocyclic carbaldehydes with furanones – An investigation of reactivity and regioselectivity
Uhrner, Fabian,Lederle, Felix,Namyslo, Jan C.,Gjikaj, Mimoza,Schmidt, Andreas,Hübner, Eike G.
, p. 4472 - 4480 (2017)
The aldol reaction of N-heterocyclic carbaldehydes with furan-2-ones has been investigated. Very mild and metal-free reaction conditions have been applied. The substitution pattern of the product was found to be controlled by the aldehyde. A detailed inve
A New Stereospecific Route to α-Alkylidene γ-Lactones
Jackson, W. Roy,Perlmutter, Patrick,Smallridge, Andrew J.
, p. 1509 - 1510 (1985)
Hydrocyanation of a range of protected β-hydroxyalkynes gives unsaturated nitriles which can be cyclised to α-alkylidene γ-lactones and in most cases the regioselectivity of hydrocyanation can be controlled giving the desired cyanoalkenes with stereospecific formation of the E-isomer.
Stereoselective Synthesis of (E)- or (Z)-α-Alkylidene-γ-butyrolactone from γ-Butyrolactone and Bis Disulfide and Mechanistic Studies of the Effect of Metal Complexes on the Stereoselection
Matsui, Syuichi
, p. 1853 - 1866 (1987)
Treatment of γ-butyrolactone with bis disulfide in presence of 2.2. equiv of lithium diisopropylamide (LDA) produced lithium enolate of O-ethyl S-(tetrahydro-2-oxo-3-furanyl) dithiocarbonate, which reacted with an aldehyde to afford exclusively (E)-α-alkylidene-γ-butyrolactone.Interestingly, when the reaction was quenched below -20 deg C or when it was carried out in the presence of metal complex such as zinc chloride, copper(I) iodide, or tributyltin chloride, (Z)-α-alkylidene-γ-butyrolactone was obtained as the major product.The stereoselectivity of this reaction was sensitive to the reaction temperature and the metal cation employed.
Synthesis of α-amino γ-butyrolactone derivatives by aziridination of α-ylidene γ-butyrolactones
Gasperi, Tecla,Loreto, M. Antonietta,Tardella, Paolo A.,Veri, Elisabetta
, p. 4953 - 4956 (2003)
The reactions of exocyclic α,β-unsaturated γ-lactones with NsONHCO2Et and CaO produce N-(ethoxycarbonyl) spiroaziridino γ-lactones. By reaction with acetic acid these products give ring opening reaction and acetylated N-protected α-amino γ-butyrolactones are obtained. The ring opening reaction is quantitative and highly regioselective.
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
Ligand-Controlled Palladium-Catalyzed Carbonylation of Alkynols: Highly Selective Synthesis of α-Methylene-β-Lactones
Beller, Matthias,Ge, Yao,Jackstell, Ralf,Jiao, Haijun,Liu, Jiawang,Spannenberg, Anke,Yang, Ji,Ye, Fei
supporting information, p. 21585 - 21590 (2020/09/23)
The first general and regioselective Pd-catalyzed cyclocarbonylation to give α-methylene-β-lactones is reported. Key to the success for this process is the use of a specific sterically demanding phosphine ligand based on N-arylated imidazole (L11) in the presence of Pd(MeCN)2Cl2 as pre-catalyst. A variety of easily available alkynols provide under additive-free conditions the corresponding α-methylene-β-lactones in moderate to good yields with excellent regio- and diastereoselectivity. The applicability of this novel methodology is showcased by the direct carbonylation of biologically active molecules including natural products.
Rhodium-catalyzed asymmetric hydrogenation of exocyclic α,β-unsaturated carbonyl compounds
Yang, Jiaxin,Li, Xiuxiu,You, Cai,Li, Shuailong,Guan, Yu-Qing,Lv, Hui,Zhang, Xumu
supporting information, p. 856 - 859 (2020/02/15)
A highly enantioselective hydrogenation of exocyclic α,β-unsaturated carbonyl compounds catalyzed by Rh/bisphosphine-thiourea (ZhaoPhos) has been developed, giving the corresponding α-chiral cyclic lactones, lactams and ketones with high yields and excellent enantioselectivities (up to 99% yield and 99% ee). Remarkably, the hydrogen bond between the substrate and the catalyst plays a critical role in this transformation. The synthetic utility of this protocol has been demonstrated by efficient synthesis of chiral 3-(4-fluorobenzyl)piperidine, a key chiral fragment of bioactive molecules.
Phosphetane oxides as redox cycling catalysts in the catalytic wittig reaction at room temperature
Longwitz, Lars,Spannenberg, Anke,Werner, Thomas
, p. 9237 - 9244 (2019/10/08)
Recently, phosphorus redox cycling has gained significant importance for a number of transformations originally requiring the use of stoichiometric amounts of phosphorus reagents. While these methodologies have several benefits, high catalyst loadings (≥10 mol percent) and harsh reaction conditions (T ≥ 100 °C) often limit their versatility and applicability. Herein, we report differently substituted phosphetane oxides as efficient catalysts for the catalytic Wittig reaction. The phosphetane scaffold is easy to modify, and a number of catalysts can be obtained in a simple two-step synthesis. The activity in the Wittig reaction significantly surpasses previously reported phospholane-based catalysts and the reaction can be conducted with catalyst loadings as low as 1.0 mol percent even at room temperature. Furthermore, a Br?nsted acid additive is no longer required to achieve high yields at these mild conditions. A methyl-substituted phosphetane oxide was employed to synthesize 25 different alkenes with yields of up to 97percent. The methodology has a good functional group tolerance and the reaction can be performed starting with alkyl chlorides, bromides, or iodides. Additionally, it was possible to use poly(methylhydrosiloxane) as the terminal reductant in the catalytic Wittig reaction employing 2-MeTHF as a renewable solvent. The intermediates of the Wittig reaction were analyzed by 31P NMR spectroscopy, and in situ NMR experiments confirmed phosphane oxide as the resting state of the catalyst. Further kinetic investigations revealed a striking influence of the base on the rate of phosphane oxide reduction.
Bioactivity-guided mixed synthesis and evaluation of α-alkenyl-γ and δ-lactone derivatives as potential fungicidal agents
Wu, Yong-Ling,Gao, Yan-Qing,Wang, De-Long,Zhong, Chen-Quan,Feng, Jun-Tao,Zhang, Xing
, p. 56496 - 56508 (2017/12/27)
In view of the great antifungal activities of sesquiterpene lactones and natural product Tulipalin A, 52 derivatives derived from α-methylene-γ-butyrolactone substructures were synthesized to study antifungal activities. In vitro and in vivo antifungal activity results revealed that compounds 2-25, which contain a γ-butyrolactone scaffold and cinnamic aldehyde moiety, have greater potent fungicidal activity than other compounds. The preliminary structure-activity relationships (SARs) demonstrated that compounds with electron-withdrawing groups and small steric hindrance would have more desirable potency. Meanwhile, the quantitative structure-activity relationship (QSAR) model (R2 = 0.947, F = 65.77, and S2 = 0.0028) revealed a convincing correlation of antifungal activity against B. cinerea with molecular structures of title compounds. The present study provided a more detailed insight into the antifungal activity of the α-methylene-γ-butyrolactone substructure, which provided a potential expectation for the exploration of α-alkenyl-γ-butyrolactone structures in agriculture.
