4071-58-3Relevant academic research and scientific papers
Formal (3+3) cycloaddition of silyl enol ethers catalyzed by trifric imide: Domino michael addition-claisen condensation accompanied with isomerization of silyl enol ethers
Azuma, Takumi,Takemoto, Yoshiji,Takasu, Kiyosei
scheme or table, p. 1190 - 1193 (2011/10/09)
We describe here a Tf2NH-catalyzed formal (3+3) cycloaddition of silyl enol ethers with acrylates as a new domino reaction. In the domino sequence, the catalyst activates Michael addition, deprotonation of the resulting silyloxonium cation and
Reductive intramolecular Henry reactions induced by Stryker's reagent
Chung, Wing Ki,Chiu, Pauline
, p. 55 - 58 (2007/10/03)
Conjugate reductions of nitroalkenes by Stryker's reagent are ensued by intramolecular aldol reactions to produce β-nitroalcohols in good yield, constituting the first examples of reductive Henry reactions.
Lewis Acid Catalysed Michael-type Addition. A New Regio- and Diastereoselective Annulation Method using Methyl Vinyl Ketone
Duhamel, Pierre,Dujardin, Gilles,Hennequin, Laurent,Poirier, Jean-Marie
, p. 387 - 396 (2007/10/02)
A new annulation method is presented, involving a boron trifluoride catalysed Michael addition of trialkylsilyl enol ethers to methyl vinyl ketone (MVK) in the presence of a hydroxylic compound.This methodology allows regiospecific 3-oxobutylation of eith
Organotin Triflate as Practical Catalyst for Michael Addition of Enol Silyl Ethers
Sato, Tsuneo,Wakahara, Yoshiyuki,Otera, Junzo,Nozaki, Hitosi
, p. 9773 - 9782 (2007/10/02)
Dibutyltin bis(triflate) is a mild Lewis acid which catalyzes clean Michael addition of enol silyl ethers.The new catalyst allows to employ various labile acceptors such as methyl vinyl ketone and 2-cyclopentenone which do not undergo smooth reaction with
Chiral 2,2-Disubstituted Cyclohexanones; Annulation via Claisen Rearrangement Products
Grattan, T. J.,Whitehurst, J. S.
, p. 11 - 18 (2007/10/02)
The methyl enol ether of 2-methylcyclohexanone reacts regiospecifically with the optical active forms of but-3-yn-2-ol and but-3-en-2-ol. (R)-But-3-yn-2-ol yields an approximately 4:1 mixture of (R)-2-methyl-2-(R-buta-1,2-dienyl)cyclohexanone and the corresponding SR compound.By contrast the but-3-en-2-ol reaction is ca. 96percent enantioselective; (R)-but-3-en-2-ol gives (R)-2-(trans-but-2-enyl)-2-methylcyclohexanone and (S)-but-3-en-2-ol gives the corresponding (S)-cyclohexanone.These Claisen rearrangement products have been transformed into Robinson-type annulated ketones.Cleavage of some highly hindered esters has been carried out efficiently by sodium methylsulphinyl-methanide in dimethyl sulphoxide.
Organotin triflates as functional Lewis acids. A new entry to simple and efficient Robinson annulation
Sato, Tsuneo,Wakahara, Yoshiyuki,Otera, Junzo,Nozaki, Hitosi
, p. 1581 - 1584 (2007/10/02)
An efficient Robinson annulation has been established through the Michael addition of enol silyl ethers to α-enones catalyzed by dibutyltinbis(triflate) followed by the MeONa-mediated intramolecular aldol condensation of the adducts.
Enolic Ortho Esters. II Tandem Nucleophilic/Electrophilic Dimethylation of 4',4'-Dimethyl-3,4,5,8-tetrahydrospiro dioxolan>
Collins, David J.,Rutschmann, Suzanne B.
, p. 1447 - 1454 (2007/10/02)
Reaction of 4,4'-dimethyl-3,4,5,8-tetrahydrospirodioxolan> (9) with methylmagnesium iodide in benzene or toluene at 40 deg gave the iodomagnesium enolate acetal (10) which upon in situ reaction with methyl iodide afforded 56percent of pure 6ξ-methyl-6-cyclohex-3-en-1-one (11), the product of tandem nucleophilic/electrophilic dimethylation.Aqueous ammonium chloride workup of the iodomagnesium enolate (10) gave 6-cyclohex-3-en-1-one (7).Some further transformations of the methylated keto acetal (11) are described.
Synthesis of Methyl Ester of 7-Oxo-11-nordrim-8-en-12-oic Acid, a Metabolite of the Fungus Lepista glaucocana (Bres.) Singer
Janaki, S.,Subba Rao, G. S. R.
, p. 505 - 507 (2007/10/02)
Synthesis of methyl ester of 7-oxo-11-nordrim-8-en-12-oic acid (8) is described.
A CONVENIENT PROCEDURE FOR CARBOXYLATION-ROBINSON ANNULATIONS OF KETONES USING TRIETHYLAMINE BASE IN THE PRESENCE OF MAGNESIUM CHLORIDE
Olsen, Richard S.,Fataftah, Zakaria A.,Rathke, Michael W.
, p. 1133 - 1140 (2007/10/02)
Carboxylation of ketones with carbon dioxide in the presence of magnesium chloride and triethylamine followed by reaction with methyl vinyl ketone gives satisfactory yields of Michael and Robinson annulation products.
1,5-DICARBONYL COMPOUNDS A GENERAL PREPARATION METHOD
Duhamel, P.,Hennequin, L.,Poirier, J. M.,Tavel, G.,Vottero, C.
, p. 4777 - 4786 (2007/10/02)
In this report, a general method for the preparation of 1,5-dicarbonyl compounds and six membered ring annelation is described.This method involves the reaction of hemiacetal vinylogs 1 with enol ethers 2 or 3 in the presence of a Lewis acid.This reaction was successfully applied to the enol ethers of α and α,α'-hindered ketones such as 2,2,6-trimethyl cyclohexanone. α-Cyperone and 6-epi-α-cyperone were obtained using this process.
