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A diastereoselective three-component synthesis of chiral 2-(1,2-diaminoalkyl)phenols from an electron-rich phenol, an amine, and a chiral alpha -N,N-dibenzylamino aldehyde is developed. The diastereoselectivity of this phenolic Mannich reaction is temp.-de ...
Chiral esters and amides (I) of pyrrolidine-2-carboxylic acid are new. - Chiral esters and amides of pyrrolidine-2-carboxylic acid, having formula (I), are new. - A = groups F1 or F2; - R' and R'' = 1-20C hydrocarbyl, i.e. acyclic, linear or branched, satu ...
Clusters of metal atoms at a fixed size can assume different structural arrangements, known as isomers, which may have nearly the same energy. Therefore at given experimental conditions distribution of these isomers can be present. While the size selection ...
Enhanced activity, lower catalyst loading, shorter reaction time, and expanded substrate scope are the advantages of [Mn(dpm)3] over Co catalysts in the hydrohydrazination reaction of alkenes. Thus, sterically hindered alkenes, including tetrasubstituted a ...
Conversion of unactivated olefins to azides was achieved with high Markovnikov selectivity for a broad range of alkenes by using 6 mol % Co(BF4).6H2O and ligand I, with 3 equiv of tosyl azide as the nitrogen source and simple silanes (e.g., PhSiH3, tetrame ...
A visible-pump/UV-probe transient absorption is used to characterize the ultrafast dynamics of bacteriorhodopsin with 80-fs time resoln. We identify three spectral components in the 265- to 310-nm region, related to the all-trans retinal, tryptophan (Trp)- ...
In the presence of sulfur dioxide and an acid promoter, (-)-(1E,3Z)-2-methyl-1-((1S)-1-phenyleth- oxy)penta-1,3-dien-3-yl isobutyrate reacts with (Z)-3-(trimethylsilyloxy)-pent-2-ene giving a silyl sulfinate intermediate that undergoes, in the presence of ...
A series of trans-platinum(IV) complexes with functionalized aromatic carboxylate ligands, cis,cis,trans-Pt(NH3)2Cl2(CO2C6H4R)2 (R = H (3), p-vinyl (4), p-methoxy (5), p-iodo (6), ...
The conformational analysis of a series of configurational isomers of 2-(hydroxymethyl)azepan-3,4,5,6-tetrols 1-4 has been carried out. H-1 NMR spectroscopic data, especially vicinal J couplings and nuclear Overhauser enhancements (NOE), assisted by molecu ...
The labile cobalt (II) complex [Co(TUF)2(Pic)2] with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TUF) bidentate and 4-methylpyridine (Pic) monodentate ligands was studied by variable temp. (VT) 19F NMR from 184 to 312 K. In contrast to the solid state, ...