52978-85-5Relevant academic research and scientific papers
Reaction of 2-(Ethoxycarbonyl)pentadienylsilane under Ritter Condition. Formation of α-Methylene-γ-lactone by Self-cyclization
Kuroda, Chiaki,Mitsumata, Naoko
, p. 1375 - 1378 (1994)
An acylative C(3)-C(4)-bond cleavage of 4,5-disubstituted 2-trimethylsilylmethyl-penta-2,4-dienoate occurred by treatment with trifluoromethanesulfonic acid in nitriles, while a self-cyclization giving an α-methylene-γ-lactone also occurred when the reactions were carried out in bulky nitriles.
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.
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.
Ruthenium-Catalyzed Cyclocarbonylation of Allenyl Alcohols and Amines: Selective Synthesis of Lactones and Lactams
Yoneda, Eiji,Zhang, Shi-Wei,Zhou, Da-Yang,Onitsuka, Kiyotaka,Takahashi, Shigetoshi
, p. 8571 - 8576 (2007/10/03)
Allenyl alcohols such as 4-hydroxybuta-1,2-dienes and 5-hydroxypenta-1,2-dienes having a variety of substituents undergo cyclocarbonylation in the presence of a ruthenium catalyst under mild conditions selectively to give five- and six-membered lactones in a high yield with 100% atom economy. 5-Aminopenta-1,2-dines are also cyclocarbonylated to give γ-lactams. A possible carbonylation mechanism involving a ruthenium cluster intermediate is proposed on the basis of experimental results.
Direct indium-promoted preparation of α-methylene-γ-lactones from 2- (bromomethyl)acrylic acid and carbonyl compounds
Choudhury, Prabir K.,Foubelo, Francisco,Yus, Miguel
, p. 10779 - 10788 (2007/10/03)
The reaction of 2-(bromomethyl)acrylic acid (2) with different carbonyl compounds 1 [CH2O, (E)-CH3CH=CHCHO, (i)PrCHO, (t)BuCHO, PhCHO, CH3(CH2)5CHO, c-C6H11CHO, Ph2CHCHO, (CH2)5CO, furfural, 1,4- cyclohexanedione, 2-chlorocyclohexanone, 2-hydroxybenzaldehyde, phthaldehyde, N-Boc-3-indolecarboxaldehyde, cholestanone, (1R)-(-)-myrtenal] and indium powder in a 1:1 THF:H2O mixture at room temperature affords, after acidic work-up with 6M hydrochloric acid, the corresponding α-methylene-γ-lactones 3.
Indium-promoted preparation of substituted α-methylene-γ-lactones from 2-(bromomethyl)acrylic acid and carbonyl compounds
Choudhury, Prabir K.,Foubelo, Francisco,Yus, Miguel
, p. 3581 - 3584 (2007/10/03)
The reaction of 2-(bromomethyl)acrylic acid (1) with different carbonyl compounds (2) [CH20, (E)-CH3CH=CHCHO, Pr(i)CHO, Bu(t)CHO, PhCHO, CH3(CH2)5CHO, c-C6H11CHO, Ph2CHCHO, (CH2)5CO] and indium powder in a 1:1 THF:H20 mixture at room temperature affords, after acidic work-up with hydrochloric acid, the corresponding α-methylene-γ-butyrolactones 3.
Catalytic acryloxypalladation of vinylcycloalkanes and exo-methylene cycloalkanes. Mechanistic insights into the competition between allylic acryloxypalladation and formation of a-methylene y-butyrolactones
Ferret, Nicolas,Mussate-Mathieu, Laurence,Perfetti, Patricia,Zahra, Jean-Pierre,Waegell, Bernard
, p. 1023 - 1031 (2007/10/03)
Acryloxypalladation of ezo-methylenecycloalkanes (three-, four-, five- and six-membered rings) and vinylcycloalkanes (three-, five- and six-membered rings) in the presence of the Pd(OAc)2/p-benzoquinone/MnC>2 catalytic system is reported. Except for the case of eio-methylenecyclopropane, this reaction provides a rapid entry to the corresponding Q-metliylene -/-butyrolactone, which essentially results from a 1,2-Markovnikov acryloxypalladation addition on the double bond. The subsequent insertion of the acrylate double bond into the carbon-palladium bond is followed by a β-elimination step. However, this reaction competes with the formation of intermediate -allyl complexes which yields the corresponding allylic acrylates. The ratio of butyrolactones to allylic acrylates is dependent on ring size. Elsevier,.
An Acylative C-C Single-Bond Cleavage and a Self-Cyclization of Ethyl 2-(Trimethylsilylmethyl)penta-2,4-dienoate or Its Free Acid under Ritter Condition
Kuroda, Chiaki,Mitsumata, Naoko,Tang, Chen Ying
, p. 1409 - 1416 (2007/10/03)
An acylative C(3)-C(4)-bond cleavage of ethyl 4,5-disubstituted 2-(trimethylsilylmethyl)penta-2,4-dienoate occurred to give an ethyl 2-(2-oxoalkyl)acrylate by treatment with trifluoromethanesulfonic acid in nitriles. A self-cyclization also occurred to give a 5,5-disubstituted 3-methylenetetrahydrofuran-2-one when the reactions were carried out in bulky nitriles. Only self-cyclization proceeded when the corresponding 4,5-disubstituted 2-(trimethylsilylmethyl)penta-2,4-dienoic acid was treated in acetonitrile. The reaction mechanism is described.
Allyltin trihalides: direct synthesis and reactivity
Fouquet, Eric,Gabriel, Andreas,Maillard, Bernard,Pereyre, Michel
, p. 590 - 598 (2007/10/02)
Stable functionalized allyltin trihalides 2 are prepared in excellent yields by direct reaction of stannous halides with allyl bromide precursors 1.They can be alkylated providing a straightforward route to useful functionalized allyltrialkylstannanes 6.C
Electrogenerated Zinc as the Catalyst in the Allylation of Carbonyl Compounds. Direct Synthesis of α-Methylene-γ-Lactones
Rollin, Y.,Derien, S.,Dunach, E.,Gebehenne, C.,Perichon, J.
, p. 7723 - 7732 (2007/10/02)
The electroreduction of a catalytic amount of ZnBr2 in acetonitrile provided a active Zn*, able to catalyze the reductive coupling of allyl bromides and chlorides with carbonyl compounds with high regioselectivity.Substituted α-methylene γ-lactones were o
