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Stereochemical Control (stereochemical + control)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Stereochemical Control by an Ester Group or Olefin Ligand in Platinum-Catalyzed Carboalkoxylation of 6-(1-Alkoxyethoxy)- hex-2-ynoates

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009
Itaru Nakamura
Abstract The cyclization of 6-(1-alkoxyethoxy)hex-2-ynoantes in the presence of the platinum-olefin catalyst system gave the corresponding multisubstituted 2-[dihydrofuran-2(3H)-ylidene]acetates in good to high yields. The Z/E selectivity is controlled by the electronic property of the ester group; the 2,2,2-trichloroethyl ester yielded the Z isomer, while the phenyl ester gave the E isomer. Moreover, we found that the Z/E selectivities in the reaction of phenyl esters 1h, 1n, and 1o were controlled by the olefin ligand. For example, the platinum-catalyzed reaction of 1h using 1,5-hexadiene as the olefin ligand gave E - 2h as the major product, while that using 1,5-cyclooctadiene produced mainly the Z isomer. [source]

ChemInform Abstract: Stereochemical Control by an Ester Group or Olefin Ligand in Platinum-Catalyzed Carboalkoxylation of 6-(1-Alkoxyethoxy)-hex-2-ynoates

CHEMINFORM, Issue 38 2009
Itaru Nakamura
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Stereochemical Control in the Reduction of 2-Chromanols.

CHEMINFORM, Issue 7 2007
Kelin Li
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Stereochemical Control of the Passerini Reaction.

CHEMINFORM, Issue 10 2005
Peter R. Andreana
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Highly Enantioselective Biphasic Iminium-Catalyzed Epoxidation of Alkenes.

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009
On the Importance of the Counterion, of N(sp2)C(sp3) Rotamers
Abstract Diastereomeric biaryliminium cations made of an (Ra)-5,5,,6,6,,7,7,,8,8,-octahydrobinaphthyl core and exocyclic appendages derived from (S)- or (R)-3,3-dimethylbutan-2-amine are effective asymmetric epoxidation catalysts for unfunctionalized alkenes. Herein, we report that the negative counterion of the iminium salts has to be chosen wisely. While the hexafluoroantimonate anion [SbF6,] is optimal for reliable results, one has to be careful about other anions and tetraphenylborate [BPh4,] in particular. We also detail that the so far unexplained "lack" of stereochemical control from the chiral exocyclic appendage in this type of catalysts is due to the existence of atropisomers around the N(sp2)C(sp3) bond that links the azepinium core to the exocyclic stereocenter. Finally, we develop a general model to predict with certainty the high selectivity in the formation of non-racemic epoxides of defined absolute configuration. [source]

ChemInform Abstract: One-Step Synthesis of Thiazolo[3,2-a]pyridines by a Multicomponent Reaction of ,-Enaminonitriles, ,,,-Unsaturated Aldehydes, and 2-Aminothiol Hydrochlorides.

CHEMINFORM, Issue 35 2010
Monica Perez-Perrino
Abstract Although the synthetic interest for the multicomponent preparation of the title thiazolopyridines is evident, the stereochemical control is rather low. [source]