| 摘要 |
<p>D- and L- α-amino acids and D- and L- α-amino aldehydes are synthesized from olefin substrates in two steps. The first step is a catalyzed asymmetric aminohydroxylation addition reaction to the olefin substrate. The addition reaction is catalyzed by osmium and is co-catalyzed by chiral ligands. The chiral ligands, in addition to being co-catalysts with the osmium, also serve to direct the addition reaction regioselectively and enantioselectively. Divalent ligands are preferred over monovalent ligands because of their enhanced regio- and enantio-selectivity. As an oxidant nitrogen source for the addition reaction, either a carbamate or sulfonamide may be employed. If carbamate is employed as an oxidant nitrogen source, the resultant β-hydroxycarbamate is deprotected to yield the corresponding β-hydroxyamine. If sulfonamide is employed as an oxidant nitrogen source, the resultant β-hydroxysulfonamide is deprotected to yield the corresponding β-hydroxyamine. The resultant β-hydroxamine is then selectively oxidized in a second synthetic step to produce the desired D- and L- α-amino acid or D- and L- α-amino aldehyde.</p> |
