39180-02-4Relevant academic research and scientific papers
Asymmetric hydrogenation of 1-alkyl and 1-aryl vinyl benzoates: A broad scope procedure for the highly enantioselective synthesis of 1-substituted ethyl benzoates
Kleman, Patryk,Gonzlez-Liste, Pedro J.,Garca-Garrido, Sergio E.,Cadierno, Victorio,Pizzano, Antonio
, p. 4398 - 4408 (2015/02/05)
The enantioselective hydrogenation of enol esters of formula CH2=C(OBz)R with rhodium catalysts based on phosphine-phosphite ligands (P-OP) has been studied. The reaction has a broad scope, and it is suitable for the preparation of products pos
Highly enantioselective hydrogenation of 1-alkylvinyl benzoates: A simple, nonenzymatic access to chiral 2-alkanols
Kleman, Patryk,González-Liste, Pedro J.,García-Garrido, Sergio E.,Cadierno, Victorio,Pizzano, Antonio
supporting information, p. 16209 - 16212 (2013/12/04)
Going chiral! Highly enantioselective catalytic hydrogenations of enol esters 1 by using a Rh catalyst bearing a P?￡?OP ligand are described (see scheme; NBD=norbornadiene). The catalytic system has a broad scope and allows the preparation of a wide range of chiral esters 2 bearing diverse alkyls or a benzyl group with high enantioselectivities. These esters can easily be converted in highly enantioenriched 2-alkanols. Copyright
Highly enantioselective Rh-catalysed hydrogenation of 1-alkyl vinyl esters using phosphine-phosphoramidite ligands
Konrad, Tina Maria,Schmitz, Pascal,Leitner, Walter,Francio, Giancarlo
supporting information, p. 13299 - 13303 (2013/10/08)
MatPhos, a good mate for hard tasks: The asymmetric hydrogenation of 1-alkyl vinyl esters, thwarted so far by mediocre ee values and low activities, can now be achieved with MatPhos/Rh catalysts with ee values of 96-99 % for a variety of substrates at low catalyst loadings (0.1-1 mol %) and under mild conditions (5-20 bar H2, room temperature). After hydrolysis, the corresponding chiral secondary alkyl alcohols can be obtained in high enantiopurities providing a general and practical route to this important product class. Copyright
Rh(I)/DpenPhos catalyzed asymmetric hydrogenation of enol esters and potassium (E)-3-cyano-5-methylhex-3-enoate
Liu, Yan,Wang, Zheng,Ding, Kuiling
experimental part, p. 7581 - 7585 (2012/09/07)
Rh(I) complexes of a class of modular chiral monodentate phosphoramidites were highly efficient for the asymmetric hydrogenation of enol esters bearing α-aryl or α-alkyl groups, to afford the corresponding hydrogenation products in high enantioselectiviti
Bi(III) carboxylates as efficient reagents for preparation of esters under mild conditions. A new method for the protection of carboxylic acids
Keramane, El-Mehdi,Boyer, Bernard,Roque, Jean-Pierre
, p. 855 - 857 (2007/10/03)
Bi(III) carboxylates have been obtained by reaction of triphenylbismuth with various monocarboxylic acids. By a ligand-exchange reaction, these Bi(III) carboxylates react with tertiary or benzylic-type bromides and afford esters. This reaction sequence constitutes a new efficient way for the temporary protection of carboxylic acids under mild conditions.
Direct transacylation of 2,2,2-trihaloethyl esters with amines and alcohols using phosphorus(III) reagents for reductive fragmentation and in situ activation
Hans, Jeremy J.,Driver, Russell W.,Burke, Steven D.
, p. 2114 - 2121 (2007/10/03)
Amides and esters have been synthesized from 2,2,2-trihaloethyl esters in one pot using phosphorus(III) reagents as reductants, with resultant carboxylate activation as an acyloxyphosphonium intermediate, and in situ trapping by amine or alcohol nucleophiles. Secondary and tertiary amides were synthesized, including a dipeptide, in good yields using hexamethylphosphorous triamide, (Me2N)3P, as reducing agent. Optimal yields of esters derived from primary and secondary alcohols were obtained using tributylphosphine and DMAP. Tribromoethyl esters provided yields superior to those obtained with trichloroethyl esters.
Oxidation of Alkynes by Hydrogen Peroxide Catalyzed by Methylrhenium Trioxide
Zhu, Zuolin,Espenson, James H.
, p. 7728 - 7732 (2007/10/03)
The oxidation of alkynes with hydrogen peroxide is catalyzed by methylrhenium tioxide.The reactions can be rationalized by postulating that an oxirene intermediate is formed between a rhenium peroxide and the alkyne.Internal alkynes yield α-diketones and carboxylic acids, the latter from the complete cleavage of the triple bonds.Rearrangement products were observed only for aliphatic alkynes.Terminal alkynes gave carboxylic acids and their derivatives and α-keto acids as the major products, but their yields varied with the solvent used.
EFFECTIVE SYNTHESIS OF ENANTIOMERIC 2-PENTANOLS AND CHIRAL DOMINICALURES BASED ON THEM
Cheskis, B. A.,Shpiro, N. A.,Moiseenkov, A. M.
, p. 1613 - 1616 (2007/10/02)
The (S) and (R) enantiomers of sec-amyl-2-methyl-(2E)-pentenoate and 2,4-dimethyl-(2E)-pentenoate (dominicalure 1 and dominicalure 2 respectively), which are contained in the aggregation pheromone of the lesser grain borer Rhizopertha dominica, were synthesized by the acylation of (S)- and (R)-2-pentanols. (2S)-Pentanol was obtained in five stages with an overall yield of > 50percent from (S)-ethyl lactate with cross-coupling of the p-toluenesulfonate of (2S)-(2-tetrahydropyranyloxy)-1-propanol with lithium diethylcuprate at the key stage.Zinc chloride can be used as an effective catalyst for the removal of the tetrahydropyranyl protection under mild conditions. (2R)-Pentanol was prepared by inversion of the configuration of its (S) enantiomer by the Mitsunobu method.
