Highlyenantioselectiveco-catalyticdirectaldolreactions by a combination of simple hydrophobic acyclicaminoacid and hydrogen-bonddonatingcatalysts are presented. The corresponding aldol products are formed in high yields with high regio-, diastereo- (anti or syn) and enantioselectivity (up to 99.5:0.5 er). The catalyst loadings can be decreased to as little as 2 mol%.
proteinogenic amino acids have been investigated in the aldolreaction of aldehyde and ketone in DMSO and aqueous DMSO (in the presence of three equivalents of water). Not only proline but also other amino acids promote the aldolreactionenantioselectively. The effect of water varies with amino acid, and water does not affect the enantioselectivity in most cases, the exceptions being Pro, Ser and His
已经研究了 20 种蛋白质氨基酸在 DMSO 和水性 DMSO(存在三当量水)中醛和酮的羟醛反应中的作用。不仅脯氨酸而且其他氨基酸也对映选择性地促进醛醇反应。水的作用因氨基酸而异,大多数情况下水不影响对映选择性,Pro、Ser和His除外。在 Pro 的情况下,在 α-取代的甲基酮的反应中观察到对非对映选择性和对映选择性有很大的积极影响,而在甲基酮的反应中没有观察到影响。