16822-06-3Relevant articles and documents
Indium mediated intramolecular carbocyclization in aqueous media. A facile and stereoselective synthesis of fused α-methylene-γ-butyrolactones
Bryan, Vernal J.,Chan, Tak-Hang
, p. 5341 - 5342 (1996)
Indium mediated intramolecular carbocyclization in aqueous media gave cis-fused α-methylene-γ-butyrolactones selectively in good yields.
NOVEL SYNTHESIS OF alpha -METHYLENE- gamma BUTYROLACTONES.
Saimoto,Nishio,Yamamoto,Shinoda,Hiyama,Nozaki
, p. 3093 - 3098 (1983)
A new method is reported for constructing alpha -methylene- gamma -butyrolactone moiety under neutral, anhydrous conditions. Olefin-dibromocarbene adducts were transformed into methyl 1-(dimethylaminoethyl)cyclopropanecarboxylates. Treatment with trimethylsily iodide followed by thermolytic distillation of the crude products gave alpha -methylene gamma -butyrolactones with high regio- and stereoselectivity.
Indirect Electroreductive Radical Cyclization of Halogeno Ethers using Nickel(II) Complexes as Electron-transfer Catalysts
Ozaki, Shigeko,Matsushita, Hidenori,Ohmori, Hidenobu
, p. 1120 - 1122 (1992)
Indirect electrochemical radical cyclization of halogeno ethers is achieved under mild conditions using nickel(II) complexes as electron-transfer catalysts.
Strain-Driven Dyotropic Rearrangement: A Unified Ring-Expansion Approach to α-Methylene-γ-butyrolactones
Lei, Xiaoqiang,Li, Yuanhe,Lai, Yang,Hu, Shengkun,Qi, Chen,Wang, Gelin,Tang, Yefeng
supporting information, p. 4221 - 4230 (2020/12/22)
An unprecedented strain-driven dyotropic rearrangement of α-methylene-β-lactones has been realized, which enables the efficient access of a wide range of α-methylene-γ-butyrolactones displaying remarkable structural diversity. Several appealing features of the reaction, including excellent efficiency, high stereospecificity, predictable chemoselectivity and broad substrate scope, render it a powerful tool for the synthesis of MBL-containing molecules of either natural or synthetic origin. Both experimental and computational evidences suggest that the new variant of dyotropic rearrangements proceed in a dualistic pattern: while an asynchronous concerted mechanism most likely accounts for the reactions featuring hydrogen migration, a stepwise process involving a phenonium ion intermediate is favored in the cases of aryl migration. The great synthetic potential of the title reaction is exemplified by its application to the efficient construction of several natural products and relevant scaffolds.
Synthesis of α-methylene-γ-lactone structure by cyclization of ω-formylallylsilane in water
Fukushima, Hiroki,Ikegami, Daisuke,Kuroda, Chiaki,Kobayashi, Kenichi
, p. 568 - 574 (2018/05/07)
Surfactant-type protonic acid-promoted intramolecular cyclization of functionalized allylsilanes was studied in water for the synthesis of α-methylene-γ-lactone compounds. ω-Formyl-β-(acetoxymethyl)allylsi-lane afforded carbocyclic compounds in good yields, while the cyclization product was not obtained from the corresponding β-ethoxycarbonyl derivative. It was found that (Z)-β-(acetoxymethyl)allylsilane predominantly afforded the cis-product, while (E)-β-(acetoxymethyl)allylsilane afforded both cis- and trans-products at a ratio of almost 1:1. The stereoselectivity of the cyclization reaction was almost the same as a protonic acid-promoted reaction in CH2Cl2 and was explained by an interaction between the C(Si)–C(alkene) bond and the carbonyl moiety. The cyclization products were converted to α-methylene-γ-lactone compounds.
Synthesis of bicyclic γ-butyrolactone derivatives by rhodium catalyzed intramolecular C-H insertion of α-dizao α-phosphoryl cycloalkyl esters
Shie, Jr-Yun,Zhu, Jia-Liang
, p. 1590 - 1601 (2016/03/01)
Under the catalysis of Rh2(OAc)4, several readily prepared cycloalkyl α-diazo α-phosphoryl esters undergo a intramolecular C-H insertion reaction to afford the fused bicyclic α-phosphoryl-γ-butyrolactones in varying yields (10%-80%) and dr ratios (69:14:17 to >99:1). The experimental results reveal that the reactivity of the precursors and the diastereoselectivity of the cyclization are both influenced by the ring sizes of the cycloalkyl moieties. Moreover, most of the resulting products can be further elaborated into α,α-dialkyl γ-butyrolactones via a two-step alkylation/reductive alkylation sequence with the controlled installation of two alkyl groups to the lactones. In addition, application of Horner-Wadsworth-Emmons (HWE) olefination reaction to the insertion products allows an access to bicyclic α-alkylidene-γ-butyrolactone ring systems that occur ubiquitously in biologically active natural products and synthetic molecules.
α-Alkylidene-γ-butyrolactone synthesis via one-pot C-H insertion/olefination: substrate scope and the total synthesis of (±)-cedarmycins A and B
Lloyd, Matthew G.,D'Acunto, Mariantonietta,Taylor, Richard J.K.,Unsworth, William P.
, p. 7107 - 7123 (2015/02/19)
Abstract A system for the synthesis of α-alkylidene-γ-butyrolactones via a one-pot C-H insertion/olefination sequence is described. The process is based on the rhodium catalysed C-H insertion reaction of α-diazo-α-(diethoxyphosphoryl)acetates. The mild reaction conditions, operational simplicity and ready availability of starting materials are all key features. A wide range of successful reaction systems are reported (41 examples) highlighting the generality of the method. The application of this method in the total synthesis of the natural products (±)-cedarmycins A and B is also described.
Dibromomethane as one-carbon source in organic synthesis: A versatile methodology to prepare the cyclic and acyclic α-methylene or α-keto acid derivatives from the corresponding terminal alkenes
Hon, Yung-Son,Liu, Yu-Wei,Hsieh, Cheng-Han
, p. 4837 - 4860 (2007/10/03)
Ozonolysis of mono-substituted alkenes A-1 followed by reacting with a preheated mixture of CH2Br2-Et2NH affords α-substituted acroleins A-2 in good yields. Under very mild reaction conditions, these α-substituted acroleins A-2 can be easily converted to α-methylene esters A-4, which could be further converted to the corresponding α-keto esters A-5. This methodology can be also applied to the preparation of α-methylene lactones B-4, α-methylene lactams, and α-keto lactones B-5 with various ring sizes.
Carbonylation of alkynols catalyzed by Pd(II)/2-PyPPh2 dissolved in organic solvents and in ionic liquids: A facile entry to α-methylene γ- and δ-lactones
Consorti, Crestina S,Ebeling, Gunter,Dupont, Jaírton
, p. 753 - 755 (2007/10/03)
The carbonylation of terminal 3-alkyn-1-ols and 1-alkyn-4-ols by Pd(OAc)2 associated with 2-(diphenylphosphino)pyridine (2-PyPPh2) dissolved in organic solvents or in 1-n-butyl-3-methyl imidazolium ionic liquids affords quantitatively and selectively exo-α-methylene γ- and δ-lactones, respectively. In the case of the reactions performed in ionic liquids (biphasic conditions), the lactones were isolated by simple distillation and the ionic catalyst solution can be reused.
Tungsten-Mediated Syntheses of Fused α-Methylenebutyrolactones from Propargyl Bromides Containing Tethered Aldehydes and Ketones
Shieh, Shwu-Ju,Chen, Chi-Chung,Liu, Rai-Shung
, p. 1986 - 1990 (2007/10/03)
The reaction of CpW(CO)3Na with a number of propargyl bromides with tethered aldehydes and ketones afforded η1-propargyl species that were subsequently transformed into tungsten-η3-2-(methoxycarbonyl)allyl compounds upon treatment with p-TSA/CH3OH; the overall yields exceeded 60%. Sequential treatment of these tungsten-η3-allyl complexes with NOBF4 and NaI in CH3CN led to intramolecular allyltungsten-carbonyl cyclization, yielding fused α-methylene butyrolactones of five-, six-, and seven-membered carbocyclic rings. All the reactions proceeded with high diastereoselectivities except for 9-methylene-7-oxabicyclo[4.3.0]nonan-8-one (22) and 10-methylene-8-oxabicyclo[5.3.0]decan-9-one (23). Modification of the metal center with a chloride ligand led to significant improvement of the trans-stereoselection of 22; the chloride modification did not significantly enhance stereoselection of 23. The stereochemical course of the reaction products is rationalized on the basis of a bicyclic transition-state mechanism.
