66909-43-1Relevant academic research and scientific papers
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.
METHODS FOR PHOSPHINE OXIDE REDUCTION IN CATALYTIC WITTIG REACTIONS
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Page/Page column 36; 37; 38, (2014/09/29)
A method for increasing the rate of phosphine oxide reduction, preferably during a Wittig reaction comprising use of an acid additive is provided. A room temperature catalytic Wittig reaction (CWR) the rate of reduction of the phosphine oxide is increased due to the addition of the acid additive is described. Furthermore, the extension of the CWR to semi-stabilized and non-stabilized ylides has been accomplished by utilization of a masked base and/or ylide-tuning.
Part I: The development of the catalytic wittig reaction
O'Brien, Christopher J.,Nixon, Zachary S.,Holohan, Andrew J.,Kunkel, Stephen R.,Tellez, Jennifer L.,Doonan, Bryan J.,Coyle, Emma E.,Lavigne, Florie,Kang, Lauren J.,Przeworski, Katherine C.
supporting information, p. 15281 - 15289 (2013/11/06)
We have developed the first catalytic (in phosphane) Wittig reaction (CWR). The utilization of an organosilane was pivotal for success as it allowed for the chemoselective reduction of a phosphane oxide. Protocol optimization evaluated the phosphane oxide precatalyst structure, loading, organosilane, temperature, solvent, and base. These studies demonstrated that to maintain viable catalytic performance it was necessary to employ cyclic phosphane oxide precatalysts of type 1. Initial substrate studies utilized sodium carbonate as a base, and further experimentation identified N,N-diisopropylethylamine (DIPEA) as a soluble alternative. The use of DIPEA improved the ease of use, broadened the substrate scope, and decreased the precatalyst loading. The optimized protocols were compatible with alkyl, aryl, and heterocyclic (furyl, indolyl, pyridyl, pyrrolyl, and thienyl) aldehydes to produce both di- and trisubstituted olefins in moderate-to-high yields (60-96 %) by using a precatalyst loading of 4-10 mol %. Kinetic E/Z selectivity was generally 66:34; complete E selectivity for disubstituted α,β-unsaturated products was achieved through a phosphane-mediated isomerization event. The CWR was applied to the synthesis of 54, a known precursor to the anti-Alzheimer drug donepezil hydrochloride, on a multigram scale (12.2 g, 74 % yield). In addition, to our knowledge, the described CWR is the only transition-/heavy-metal-free catalytic olefination process, excluding proton-catalyzed elimination reactions. A point of difference: By utilizing an organosilane to chemoselectively reduce a phosphane oxide precatalyst to a phosphane (see scheme), the first catalytic (in phosphane) Wittig reaction has been developed. The methodology has been applied to the synthesis of 22 disubstituted and 24 trisubstituted olefins, including a multigram synthesis of a precursor to the anti-Alzheimer drug donepezil hydrochloride.
Breaking the ring through a room temperature catalytic wittig reaction
O'Brien, Christopher J.,Lavigne, Florie,Coyle, Emma E.,Holohan, Andrew J.,Doonan, Bryan J.
supporting information, p. 5854 - 5858 (2013/06/27)
One ring no longer rules them all: Employment of 2.5-10 mol % of 4-nitrobenzoic acid with phenylsilane led to the development of a room temperature catalytic Wittig reaction (see scheme). Moreover, these enhanced reduction conditions also facilitated the use of acyclic phosphine oxides as catalysts for the first time. A series of alkenes were produced in moderate to high yield and selectivity. Copyright
Stereoselective synthesis of α-alkylidene- and substituted alkylidene- γ-lactones
?astulík, Jakub,Mazal, Ctibor
, p. 2741 - 2744 (2007/10/03)
Cross-coupling reactions of (E)- and (Z)-tosylates of α- hydroxymethylene-γ-butyrolactone with aryl, heteroaryl, alkyl, and alkynylzinc chlorides under Pd(PPh3)4 catalysis were found to be a suitable synthetic method for stereoselective preparation of α-alkylidene- and substituted alkylidene-γ-lactones. The reactions, conducted under mild conditions, proceed with high stereoselectivity and moderate yields. (C) 2000 Elsevier Science Ltd.
New Methods for Stereoselective Synthesis of α-Alkylidene-γ-butyrolactones Using Monoanion of O-Ethyl S-(Tetrahydro-2-oxo-3-furanyl) Thiocarbonate and Dianion of α-Mercapto-γ-butyrolactone
Tanaka, Kazuhiko,Uneme, Hideki,Yamagishi, Nobuyuki,Tanikaga, Rikuhei,Kaji, Aritsune
, p. 2910 - 2916 (2007/10/02)
The lithium enolates of O-ethyl S-(tetrahydro-2-oxo-3-furanyl) dithiocarbonate and thiocarbonate were found to be efficient reagents for the stereoselective synthesis of α-alkylidene-γ-butyrolactones from carbonyl compounds.The dianion of α-mercapto-γ-butyrolactone was successfully generated by treatment of α-mercapto-γ-butyrolactone with 2.2 equivalents of lithium diisopropylamide in the presence of N,N,N',N'-tetramethylethylenediamine at -78 deg C in THF.The dianion thus formed has been utilized for the efficient and stereoselective synthesis of α-alkylidene-γ-butyrolactones from carbonyl compounds.
