81640-04-2Relevant articles and documents
Titanium silicate molecular sieve, TS-1, catalysed C-C bond formation in Mukaiyama type aldol reactions
Sasidharan,Raju, Satya V. N.,Srinivasan,Paul, Vincent,Kumar
, p. 129 - 130 (1996)
The titanium silicate molecular sieve, TS-1, efficiently catalyses the formation of carbon-carbon bond in the Mukaiyama type aldol reaction of silyl enol ethers and aldehydes forming β-hydroxy esters/aldols in high yields under heterogeneous and ambient r
Highly diastereo- and enantioselective direct aldol reactions of aldehydes and ketones catalyzed by siloxyproline in the presence of water
Aratake, Seiji,Itoh, Takahiko,Okano, Tsubasa,Nagae, Norio,Sumiya, Tatsunobu,Shoji, Mitsuru,Hayashi, Yujiro
, p. 10246 - 10256 (2008/09/18)
Proline-based organocatalysts have been developed for a highly enantioselective, direct aldol reaction of aldehydes and ketones in the presence of water. While several surfactant-proline combined catalysts have proved effective, proline derivatives with a hydrophobic moiety such as rraw-siloxy-L-proline and cis-siloxy-D-proline, both of which are easily prepared from the same commercially available 4-hydroxy-L-proline. have been found to be the most effective organocatalysts examined in this study, affording the aldol product with excellent diastereo- and enantioselectivities, these two catalysts generating opposite enantiomers. Water affects the selectivity, and poor results are obtained under neat reaction conditions or in dry organic solvents. More than three equivalents of water are required for the best diastereo- and enantioselectivities. while three equivalents is the recommended amount from a synthetic point of view. The reaction proceeds in the organic phase, and also proceeds in the presence of a large amount of water. The large-scale preparation of aldols with the minimal use of an organic solvent, including in the purification step. is described.
Uncatalyzed aldol reaction using a dimethylsilyl enolate and α- dimethylsilyl ester in N,N-dimethylformamide
Miura, Katsukiyo,Sato, Hiroshi,Tamaki, Kentaro,Ito, Hajime,Hosomi, Akira
, p. 2585 - 2588 (2007/10/03)
Dimethylsilyl enolates and α-dimethylsilyl esters reacted with aldehydes in N,N-dimethyl-formamide without an activator to give aldol adducts in moderate to good yields. Under the same conditions, the corresponding trimethylsilyl derivatives exhibited lower reactivities toward the aldol reaction.
Ytterbium Trifluoromethanesulfonate Mediated Cross-Aldol Reaction between Ketones and Aldehydes
Fukuzawa, Shin-ichi,Tsuchimoto, Teruhisa,Kanai, Takeshi
, p. 2227 - 2232 (2007/10/02)
The cross-aldol reaction between a ketone and an aldehyde proceeded smoothly with threo diastereoselection favorably mediated by ytterbium trifluoromethanesulfonate and tertiary amine in diethyl ether or in dichloromethane.A ytterbium enolate was trapped
FACILE ROUTES TO BORON ENOLATES. Et3B-MEDIATED REFORMATSKY TYPE REACTION AND THREE COMPONENTS COUPLING REACTION OF ALKYL IODIDES, METHYL VINYL KETONE, AND CARBONYL COMPOUNDS
Nozaki, Kyoko,Oshima, Koichiro,Utimoto, Kiitiro
, p. 1041 - 1044 (2007/10/02)
Reaction of α-bromoketones with Ph3SnH in the presence of Et3B provides boron enolates which react with carbonyl compounds to give β-hydroxyketones in good yields.Et3B-induced Reformatsky type reaction of α-iodoketones with an aldehyde or ketone proceeds without Ph3SnH.
STEREOCHEMISTRY OF THE FLUORIDE CATALYZED ALDOL REACTION OF ENOL SILYL ETHERS. EVIDENCE FOR ANOTHER NON-CHELATE TRANSITION STATE
Nakamura, Eiichi,Yamago, Shigeru,Machii, Daisuke,Kuwajima, Isao
, p. 2207 - 2210 (2007/10/02)
Stereochemistry of the tetrabutylammonium fluoride catalyzed aldol reaction of enol silyl ethers was examined for both tri- and tetra-substitued enolates to find that the previous "extended, non-chelate" transition model (A) applicable only for enolates w
TRIMETHYLSILYL TRIFLATE CATALYZED ALDOL-TYPE REACTION OF ENOL SILYL ETHERS AND ACETALS OR RELATED COMPOUNDS
Murata, Shizuaki,Suzuki, Chikusa,Noyori, Ryoji
, p. 4259 - 4276 (2007/10/02)
Trimethylsilyl triflate with or without added hindered tertiary amines catalyzes directed condensation of enol trimethylsilyl ethers with acetals, orthoformate, or 2-acetoxytetrahydrofuran or -pyrans to give the corresponding β-alkoxy carbonyl compounds.R
Stereoselective Syntheses of Alkohols, XXV. - Generation of Enol Borates and Their Addition to Aldehydes
Hoffmann, Reinhard W.,Ditrich, Klaus,Froech, Sybille
, p. 977 - 986 (2007/10/02)
Ketone-derived enol borates, especially those having a 4,4,5,5-tetramethyl-1,3,2-dioxaborolane unit, are stable compounds,which have been prepared either by borylation of lithium enolates or by oxidation of vinylboronates.These E- or Z-enol borates add to aldehydes in a stereoconvergent reaction leading to syn-aldols.Aldehyde-derived enol borates have a high tendency towards polymerization.Their in-situ addition to aldehydes generates 4-alkoxy-1,3,2-dioxaborinanes, which are internally protected aldols.
ERYTHRO-SELECTIVE ALDOL CONDENSATION VIA ENAMINOSILANES
Ando, Wataru,Tsumaki, Hidetoshi
, p. 1409 - 1412 (2007/10/02)
In the presence of BF3*OEt2, enaminosilanes derived from acyclic and cyclic ketones have been shown to undergo erythro selective kinetic aldol condensation.
ERYTHRO SELECTIVE ALDOL CONDENSATION USING TITANIUM ENOLATES
Reetz, M. T.,Peter, R.
, p. 4691 - 4694 (2007/10/02)
Titanium enolates derived from ketones and esters react with aldehydes to afford erythro adducts with high diastereoselection.
