- Direct palladium-catalyzed carbonylative transformation of allylic alcohols and related derivatives
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A direct, palladium-catalyzed, carbonylative transformation of allylic alcohols for the synthesis of β,γ-unsaturated carboxylic acids has been developed. With formic acid as the CO source, various allylic alcohols were conveniently transformed into the corresponding β,γ-unsaturated carboxylic acids with excellent linear and (E)-selectivity. The reaction was performed under mild conditions; toxic CO gas manipulation and high-pressure equipment were avoided in this procedure.
- Wu, Fu-Peng,Peng, Jin-Bao,Fu, Lu-Yang,Qi, Xinxin,Wu, Xiao-Feng
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- Palladium-Catalyzed Low Pressure Carbonylation of Allylic Alcohols by Catalytic Anhydride Activation
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A direct carbonylation of allylic alcohols has been realized for the first time with high catalyst activity at low pressure of CO (10 bar). The procedure is described in detail for the carbonylation of E-nerolidol, an important step in a new BASF-route to (?)-ambrox. Key to high activities in the allylic alcohol carbonylation is the finding that catalytic amounts of carboxylic anhydride activate the substrate and are constantly regenerated with carbon monoxide under the reaction conditions. The identified reaction conditions are transferrable to other substrates as well.
- Schelwies, Mathias,Paciello, Rocco,Pelzer, Ralf,Siegel, Wolfgang,Breuer, Michael
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supporting information
p. 9263 - 9266
(2021/05/27)
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- Efficient Pd-Catalyzed Regio- and Stereoselective Carboxylation of Allylic Alcohols with Formic Acid
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Formic acid is efficiently used as a C1 source to directly carboxylate allylic alcohols in the presence of a low loading of palladium catalyst and acetic anhydride as additive to afford β,γ-unsaturated carboxylic acids with excellent chemo-, regio-, and stereoselectivity. The reaction proceeds through a carbonylation process with in situ-generated carbon monoxide under mild conditions, avoiding the use of high-pressure gaseous CO. A bisphosphine ligand with a large bite angle (4,5-bis{diphenylphosphino}-9,9-dimethylxanthene, Xantphos) was found to be uniquely effective for this transformation. The regio- and stereoconvergence of this reaction is ascribed to the thermodynamically favored isomerization of the allylic electrophile in the presence of the palladium catalyst.
- Fu, Ming-Chen,Shang, Rui,Cheng, Wan-Min,Fu, Yao
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supporting information
p. 8818 - 8822
(2017/07/11)
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- Tandem hydroboration/reduction of trisubstituted β,γ-unsaturated esters for the asymmetric synthesis of chiral 1,3-diols
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Treatment of a range of trisubstituted β,γ-unsaturated esters with 2 equiv of (-)-monoisopinocampheylborane results in hydroboration of their alkene functionalities and reduction of their ester groups to afford chiral 1,3-diols containing two new vicinal
- Fordred, Paul S.,Bull, Steven D.
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- Remarkable levels of enantioswitching in catalytic asymmetric hydroboration
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TADDOL-derived phosphites and phosphoramidites are effective ligands for rhodium-catalyzed asymmetric hydroborations of β,γ-unsaturated amides, achieving up to 99% ee. However, the sense of stereoinduction, R or S, is surprisingly dependent on rather subt
- Smith, Sean M.,Takacs, James M.
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supporting information; experimental part
p. 4612 - 4615
(2010/12/19)
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- An approach to enantioselective 5-endo halo-lactonization reactions
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Enantioselective lactonization of 4-substituted but-3-enoic acids using iodobis(N-methylephedrine) hexafluoroantimonate in dichloromethane at low temperatures is reported. The presence of bis(N-methylephedrine)silver(I) hexafluoroantimonate, derived from
- Garnier, Jean Marc,Robin, Sylvie,Rousseau, Gerard
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p. 3281 - 3291
(2008/02/10)
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- Preparation of enantiopure 3,5,5-trialkyl-γ-butyrolactones by diastereospecific 5-endo halo lactonizations
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A new preparation of 3,5,5-trialkyl-γ-butyrolactones of defined absolute configuration is reported. This method involves the diastereoselective alkylation of 3,4-ethylenic acids after incorporation of a chiral Evans auxiliary, and then after separation of
- Garnier, Jean-Marc,Robin, Sylvie,Guillot, Regis,Rousseau, Gerard
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p. 1434 - 1442
(2008/02/11)
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- 4-Aryl-3-butenoic acids and lower alkyl esters
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Benzyl esters and thiolesters of 4-aryl-3-butenoic acids, intermediates therefor, synthesis thereof, and the use of said esters and thiolesters for the control of pests.
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