- N-Heterocyclic carbene-catalyzed sulfa-Michael addition of enals
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An efficient N-heterocyclic carbene (NHC) catalyzed sulfa-Michael addition (SMA) between enals and thiols has been developed. Under the catalysis of 10 mol% stable free carbene IPr and with 20 mol% hexafluoroisopropanol (HFIP) as an additive, enals react with a variety of thiols to afford the SMA adducts in 54-98% yields. In this process, the free carbene preferentially interacts with thiols through hydrogen-bonding and no NHC-catalyzed extended Umpolung transformations were observed.
- Cong, Zi-Song,Li, Yang-Guo,Du, Guang-Fen,Gu, Cheng-Zhi,Dai, Bin,He, Lin
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supporting information
p. 13129 - 13132
(2017/12/26)
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- Traceless Rhodium-Catalyzed Hydroacylation Using Alkyl Aldehydes: The Enantioselective Synthesis of β-Aryl Ketones
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A one-pot three-step sequence involving Rh-catalyzed alkene hydroacylation, sulfide elimination and Rh-catalyzed aryl boronic acid conjugate addition gave products of traceless chelation-controlled hydroacylation employing alkyl aldehydes. The stereodefined β-aryl ketones were obtained in good yields with excellent control of enantioselectivity. Good variation of all three reaction components is possible.
- Bouisseau, Ana?s,Gao, Ming,Willis, Michael C.
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supporting information
p. 15624 - 15628
(2016/10/25)
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- Rhodium-catalysed intermolecular alkyne hydroacylation: The enantioselective synthesis of α- and β-substituted ketones by kinetic resolution
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Chemical Equation Presented Cleared up! Intermolecular alkyne hydroacylation represents a new addition to the range of transition- metalcatalysed hydroacylation reactions that can be performed in an enantioselective manner. By using a kinetic resolution procedure, both racemic α- and βsubstituted aldehydes can be converted into the corresponding enantiomerically enriched substituted enone products (see scheme).
- Gonzalez-Rodriguez, Carlos,Parsons, Scott R.,Thompson, Amber L.,Willis, Michael C.
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supporting information; experimental part
p. 10950 - 10954
(2010/11/05)
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- A simple, efficient, and green procedure for the 1,4-addition of thiols to conjugated alkenes and alkynes catalyzed by sodium acetate in aqueous medium
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A benign and inexpensive salt, sodium acetate, efficiently catalyzes 1,4-addition of thiols to a variety of conjugated alkenes such as ?,?-unsaturated ketones, aldehydes, carboxylic esters, nitriles, nitro compounds, and chalcones in aqueous THF. The reac
- Ranu, Brindaban C.,Mandal, Tanmay
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p. 223 - 227
(2008/02/10)
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- Rhodium-catalyzed intermolecular chelation controlled alkene and alkyne hydroacylation: Synthetic scope of β-S-substituted aldehyde substrates
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The use of β-S-substituted aldehydes in rhodium-catalyzed intermolecular hydroacylation reactions is reported. Aldehydes substituted with either sulfide or thioacetal groups undergo efficient hydroacylation with a variety of electron-poor alkenes, such as enoates, in Stetter-like processes and with both electron-poor and neutral alkynes. In general, the reactions with electron-poor alkenes demonstrate good selectivity for the linear regioisomer, and the reactions with alkynes provide enone products with excellent selectivity for the E-isomers. The scope of the process was shown to be broad, tolerating a variety of substitution patterns and functional groups on both reaction components. A novel CN-directing effect was shown to be responsible for reversing the regioselectivity in a number of alkyne hydroacylation reactions. Catalyst loadings as low as 0.1 mol % were achievable.
- Willis, Michael C.,Randell-Sly, Helen E.,Woodward, Robert L.,McNally, Steven J.,Currie, Gordon S.
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p. 5291 - 5297
(2007/10/03)
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- Rhodium-catalyzed reductive aldol reactions using aldehydes as the stoichiometric reductants
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Chelated acyl rhodium hydrides, generated from the addition of [Rh(dppe)]ClO4 to β-sulfide-substituted aldehydes, can function as the stoichiometric reductants in reductive aldol processes. Unsaturated nitriles, esters, and ketones can be used as enolate equivalents, and a variety of simple α- and β-substituted aldehydes can be employed. The use of a second, more electrophilic, aldehyde allows three-component reactions to be performed. Copyright
- Willis, Michael C.,Woodward, Robert L.
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p. 18012 - 18013
(2007/10/03)
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