The Use of pH to Influence Regio- and Chemoselectivity in the Asymmetric Aminohydroxylation of Styrenes
作者:Vitaliy Nesterenko、Joshua T. Byers、Paul J. Hergenrother
DOI:10.1021/ol027242j
日期:2003.2.1
[reaction: see text] The pH-controlled Sharplessasymmetricaminohydroxylation (AA) of styrenes provides 1-aryl-2-amino ethanols (regioisomer B) with high enantio-, chemo-, and regioselectivity. As existing AA protocols typically give regioisomer A as the major reaction product when using carbamate nitrogen sources, this method is a convenient alternative for the selective production of regioisomer
Use of a Catalytic Chiral Leaving Group for Asymmetric Substitutions at sp<sup>3</sup>
-Hybridized Carbon Atoms: Kinetic Resolution of β-Amino Alcohols by <i>p</i>
-Methoxybenzylation
catalytic strategy was developed for asymmetric substitution reactions at sp3‐hybridized carbon atoms by using a chiral alkylating agent generated in situ from trichloroacetimidate and a chiral phosphoric acid. The resulting chiral p‐methoxybenzyl phosphate selectively reacts with β‐amino alcohols rather than those without a β‐NH functionality. The use of an electronically and sterically tuned chiral
The invention relates to a process for the aminohydroxylation of alkenes using N-oxycarbamate reagents, e.g. N-acyloxycarbamate, N-alkyloxycarbonyloxycarbamate and N-aralkoxycarbonyloxycarbamate reagents. The invention particularly relates to an intermolecular aminohydroxylation reaction that can be carried out in the absence of added base. The invention also relates to novel N-oxycarbamate reagents that are stable crystalline materials. The process of the invention is useful in the synthesis of compounds having a vicinal amino alcohol moiety, such as biologically active compounds.