63814-74-4Relevant academic research and scientific papers
An amino alcohol ligand for highly enantioselective addition of organozinc reagents to aldehydes: Serendipity rules
Nugent, William A.
, p. 2133 - 2136 (2007/10/03)
(matrix presented) Amino alcohol 4 (or its enantiomer) is prepared in two simple steps. Commercial (1R,2S)-2-amino-1,2-diphenylethanol is dialkylated with bis(2-bromoethyl) ether. Subsequent hydrogenation over 5% Rh on alumina in the presence of morpholine unexpectedly stops at the hexahydro derivative 4. Amino alcohol 4 promotes the enantioselective addition of diethylzinc to aldehydes at room temperature in up to 99% enantiomeric excess.
Solvent effects in deamination reactions
Banert, Klaus,Bunse, Michael,Engbert, Theodor,Gassen, Karl-Rudolf,Kurnianto, Apriana W.,Kirmse, Wolfgang
, p. 272 - 278 (2007/10/02)
Nitrous acid deaminations of (S)-2-butanamine, (2R,3S)-3-methyl-2-pentanamine (8), cyclopropananmine (17) and 4,4-dimethyl-2-adamantanamine (30) have been studied in water and in a series of carboxylic acids of decreasing polarity (acetic, 3,3-dimethylbutyric, 2-ethylhexanoic acid).The stereochemistry of aqueous deaminations varies from predominant inversion to predominant retention, depending upon the structure of the substrate (steric hindrance, neighbouring-group participation, etc.).In carboxylic acid media, alcohols arise with predominant retention, i.e. by front-side attack of the "internal" nucleophile (water).Inverting displacement of nitrogen by the "external" nucleophile (carboxylic acid/carboxylate) increases with decreasing polarity of the solvent.Even cyclopropanamine yields cyclopropyl esters (2-10percent) of inverted configuration, as shown with the aid of deuterium labels.Current mechanistic concepts are modified to account for these results.
