- DBU-Catalyzed Ring-Opening and Retro-Claisen Fragmentation of Dihydropyranones
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We present a general protocol for the formal Michael addition of acetone to α,β-unsaturated esters and amides, a transformation difficult to perform using current methods. The protocol comprises of an amidine catalyzed relay ring-opening and fragmentation
- Axelsson, Anton,Hammarvid, Emmelie,Rahm, Martin,Sundén, Henrik
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p. 5436 - 5444
(2020/08/26)
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- Highly effective vinylogous Mukaiyama-Michael reaction catalyzed by silyl methide species generated from 1,1,3,3-tetrakis(trifluoromethanesulfonyl)propane
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(Chemical Equation Presented) Silyl methide species in situ generated from 1,1,3,3-tetrakis(trifluoromethanesulfonyl)propane (Tf2CHCH 2CHTf2) performed as an excellent acid catalyst for the vinylogousMukaiyama-Michael reaction of α,β-unsaturated ketones with 2-silyloxyfurans. Notably, the required loading of Tf2CHCH 2CHTf2 to obtain the 1,4-adducts in reasonable yield was significantly low (from 0.05 to 1.0 mol%). This carbon acid-mediatedVMMreaction provides a powerful synthetic methodology to construct highly substituted γ-butenolide structure. 2010 American Chemical Society.
- Takahashi, Arata,Yanai, Hikaru,Zhang, Min,Sonoda, Takaaki,Mishima, Masaaki,Taguchi, Takeo
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supporting information; experimental part
p. 1259 - 1265
(2010/04/29)
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- A general organocatalytic enantioselective malonate addition to α,β-unsaturated enones
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A general enantioselective organocatalytic conjugate addition procedure of a variety of malonates to α,β-unsaturated enone systems is presented. The reaction is efficiently catalysed by the pyrrolidinyl tetrazole catalyst 1. Cyclic, acyclic and aromatic e
- Wascholowski, Veit,Knudsen, Kristian Rahbek,Mitchell, Claire E. T.,Ley, Steven V.
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experimental part
p. 6155 - 6165
(2009/05/27)
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- NOVEL REFORMATSKY REACTIONS OF 3-ARYLMETHYLENE-4,5-DIHYDRO-2(3H)-FURANONES AND 4-ARYLMETHYLENE-3-METHYL-5(4H)-ISOXAZOLONES
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New avenues for enlarging the scope of Reformatsky reaction have been explored by reacting the title compounds with α-halogenoalkanoates in the presence of zinc.
- Batra, Sanjay,De, Dibyendu,Seth, Manju,Bhaduri, Amiya Prasad
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p. 1228 - 1238
(2007/10/02)
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- The Michael-type Reaction of B-Iodo-9-BBN/Ethoxyethyne Adduct to α,β-Unsaturated Ketones. A Selective Synthesis of δ-Keto Esters
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The adduct formed from B-iodo-9-borabicyclononane and ethoxyethyne reacts with α,β-unsaturated ketones under mild conditions to give δ-keto esters in excellent yield selectively.
- Kawamura, Fumitoshi,Tayano, Takao,Satoh, Yoshitaka,Hara, Shoji,Suzuki, Akira
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p. 1723 - 1726
(2007/10/02)
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- An Efficient and Convenient Method for the Preparation of α-Methylenated Ketones from Silyl Enol Ethers
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In the presence of a catalytic amount of stannous halide, silyl enol ethers react with bromomethyl methyl ether to give the corresponding α-bromoethyl ketones, which are smoothly converted to α-methylenated ketones on the successive addition of tertiary amine by one-pot procedure.This method is successfully applied to a synthesis of sarkomycin intermediate.
- Hayashi, Masaji,Mukaiyama, Teruaki
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p. 1283 - 1286
(2007/10/02)
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