Prolinamides<i>versus</i>Prolinethioamides as Recyclable Catalysts in the Enantioselective Solvent-Free Inter- and Intramolecular Aldol Reactions
作者:Diana Almaşi、Diego A. Alonso、Carmen Nájera
DOI:10.1002/adsc.200800430
日期:2008.11.3
and direct anti-aldol reaction of aliphatic ketones with aromatic aldehydes catalyzed by recyclable L-prolineamides and L-prolinethioamides 3 is studied. The L-prolinethioamide 3d (5 mol%), derived from L-Pro and (R)-1-aminoindane, is the most efficient catalyst for this process affording the anti-aldol adducts in high yields with excellent diastereo- and enantioselectivities (up to >98/2 dr, up to
研究了可回收的L-脯氨酸酰胺和L-脯氨酸硫酰胺3催化的脂肪族酮与芳族醛的无溶剂不对称和直接的抗醛醇缩合反应。衍生自L-Pro和(R)-1-氨基茚满的L-脯氨酸硫代酰胺3d(5 mol%)是该方法最有效的催化剂,可提供高收率的抗醛醇加合物,并具有出色的非对映体和对映体选择性(up在0°C或室温下达到> 98/2 dr,最高可达98%ee)。脯氨酸硫酰胺3d是有效的有机催化剂,可用于首个不对称,无溶剂的分子内Hajos-Parrish-Eder-Sauer-Wiechert反应,其对映选择性(据报道高达88%ee)与有机溶剂中的对映选择性相当或更高。而且,有机催化剂3d可以通过简单的酸/碱萃取容易地回收和再利用。