- Reaction of 2-(Ethoxycarbonyl)pentadienylsilane under Ritter Condition. Formation of α-Methylene-γ-lactone by Self-cyclization
-
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.
- Kuroda, Chiaki,Mitsumata, Naoko
-
-
Read Online
- Strain-Driven Dyotropic Rearrangement: A Unified Ring-Expansion Approach to α-Methylene-γ-butyrolactones
-
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.
- Lei, Xiaoqiang,Li, Yuanhe,Lai, Yang,Hu, Shengkun,Qi, Chen,Wang, Gelin,Tang, Yefeng
-
supporting information
p. 4221 - 4230
(2020/12/22)
-
- 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
-
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.
- Hon, Yung-Son,Liu, Yu-Wei,Hsieh, Cheng-Han
-
p. 4837 - 4860
(2007/10/03)
-
- Ruthenium-Catalyzed Cyclocarbonylation of Allenyl Alcohols and Amines: Selective Synthesis of Lactones and Lactams
-
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.
- Yoneda, Eiji,Zhang, Shi-Wei,Zhou, Da-Yang,Onitsuka, Kiyotaka,Takahashi, Shigetoshi
-
p. 8571 - 8576
(2007/10/03)
-
- Direct indium-promoted preparation of α-methylene-γ-lactones from 2- (bromomethyl)acrylic acid and carbonyl compounds
-
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.
- Choudhury, Prabir K.,Foubelo, Francisco,Yus, Miguel
-
p. 10779 - 10788
(2007/10/03)
-
- Indium-promoted preparation of substituted α-methylene-γ-lactones from 2-(bromomethyl)acrylic acid and carbonyl compounds
-
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.
- Choudhury, Prabir K.,Foubelo, Francisco,Yus, Miguel
-
p. 3581 - 3584
(2007/10/03)
-
- Catalytic acryloxypalladation of vinylcycloalkanes and exo-methylene cycloalkanes. Mechanistic insights into the competition between allylic acryloxypalladation and formation of a-methylene y-butyrolactones
-
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,.
- Ferret, Nicolas,Mussate-Mathieu, Laurence,Perfetti, Patricia,Zahra, Jean-Pierre,Waegell, Bernard
-
p. 1023 - 1031
(2007/10/03)
-
- 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
-
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.
- Kuroda, Chiaki,Mitsumata, Naoko,Tang, Chen Ying
-
p. 1409 - 1416
(2007/10/03)
-
- Allyltin trihalides: direct synthesis and reactivity
-
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
- Fouquet, Eric,Gabriel, Andreas,Maillard, Bernard,Pereyre, Michel
-
p. 590 - 598
(2007/10/02)
-
- Electrogenerated Zinc as the Catalyst in the Allylation of Carbonyl Compounds. Direct Synthesis of α-Methylene-γ-Lactones
-
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
- Rollin, Y.,Derien, S.,Dunach, E.,Gebehenne, C.,Perichon, J.
-
p. 7723 - 7732
(2007/10/02)
-
- Reactivity of functionalized allyltrihalostannanes: An easy entry to α-methylene-γ-lactones
-
Stable ester monoallyltin halides 2 are prepared in excellent yields and react easily with aldehydes and ketones under very mild conditions, to provide a usefull access to various α- methylene-γ-lactones.
- Fouquet, Eric
-
p. 7749 - 7752
(2007/10/02)
-
- A new approach for the synthesis of α-methylene-γ-butyrolactones from α-bromomethylacrylic acids (or esters)
-
This paper reports that a new approach for the synthesis of α-methylene-γ-butyrolactones from the reaction of α-bromomethyl acrylic acid (or ester), powdered tin and carbonyl compounds in one pot with excellent to good yields.
- Zhou,Lu,Wu
-
p. 481 - 487
(2007/10/02)
-
- Palladium-catalyzed carbonyl allylation by 2-(hydroxymethyl)acrylate derivatives: Synthesis of α-methylene-γ-butyrolactones
-
Ethyl 2-(hydroxymethyl)acrylate derivatives serve as reagents for 2-ethoxycarnonylallylation of carbonyl compounds using PdCl2(PhCN)2-SnCl2 system to produce α-methylene-γ-butyrolactones diastereoselectively.
- Masuyama,Nimura,Kurusu
-
p. 225 - 228
(2007/10/02)
-
- A New Synthesis of γ-Substituted α-Methylene-γ-butyrolactones (2-Methylene-4-alkanolides) using Catalysis by SnCl2/Amberlyst 15
-
Reaction of α-bromomethylacrylic acid with aldehydes or ketones in an SnCl2/amberlyst 15/THF/H2O system affords 2-methylene-4-alkanolides in mostly good yields.
- Talaga, Patrice,Schaeffer, Marcel,Benezra, Claude,Stampf, Jean-Luc
-
-
- REFORMATSKY-TYPE REACTIONS IN AQUEOUS MEDIA. USE OF BROMOMETHYLACRYLIC ACID FOR THE SYNTHESIS OF α-METHYLENE-γ-BUTYROLACTONES.
-
A new method for the preparation of α-methylene-γ-butyrolactones is described.
- Mattes, Henri,Benezra, Claude
-
p. 5697 - 5698
(2007/10/02)
-
- The Isoxazoline Route to α-Methylene Lactones.
-
A new route to α-methylene lactones, important structural subunits of many natural products, has been developed using the nitrile oxide derived from 2-nitroethanol.
- Kozikowski, Alan P.,Ghosh, Arun K.
-
p. 2623 - 2626
(2007/10/02)
-
- Concise Syntheses of 3-Methylenetetrahydrofuran-2-one Derivatives and Related Systems
-
Using the Shapiro reaction, the title compounds were prepared in 'one pot' from the consideration of two ketones, or an aldehyde and a ketone, with carbon dioxide.For example, acetone 2,4,6-tri-isopropylbenzenesulphonylhydrazone was treated in sequence with n-butyl-lithium (-50 deg C), acetone (-50 deg C), n-butyl-lithium (-78 to 0 to -78 deg C), carbon dioxide (-78 deg C), and trifluoroacetic acid (25 deg C) to give 5,5-dimethyl-3-methylenetetrahydrofuran-2-one.The reaction was extended to prepare derivatives of 3-methylenetetrahydropyran-2-one and 3,5-dimethylenetetrahydrofuran-2-one.
- Adlington, Robert M.,Barrett, Anthony G. M.
-
p. 2848 - 2863
(2007/10/02)
-
- DIANION OF N-(o-METHOXYPHENYL)-2-METHYLPROPENAMIDE: A NEW REAGENT FOR THE CONVENIENT SYNTHESIS OF α-METHYLENE-γ-BUTYROLACTONES FROM CARBONYL COMPOUNDS
-
Dianion of N-(o-methoxyphenyl)-2-methylpropenamide was successfully generated on treatment of the amide with t-BuOK-BuLi at -78 degC in THF and utilized as the key reagent for the synthesis of γ-substituted α-methylene-γ-butyrolactones.
- Tanaka, Kazuhiko,Nozaki, Yoshihito,Tamura, Norikazu,Tanikaga, Rikuhei,Kaji, Aritsune
-
p. 1567 - 1568
(2007/10/02)
-
- Synthesis of α-Methylene-γ-butyrolactones: A Structure-Activity Relationship Study of Their Allergenic Power
-
Thirty-five α-methylene-γ-butyrolactones has been prepared and their allergenic properties tested on the skin of guinea pigs experimentally sensitized to (a) alantolactone (1), (b) isoalantolactone (2), and (c) α-methylene-γ-butyrolactone (3).The two firs
- Schlewer, Gilbert,Stampf, Jean-Luc,Benezra, Claude
-
p. 1031 - 1038
(2007/10/02)
-