作者:Xiaoming Feng、Yan Xiong、Fei Wang、Shunxi Dong、Xiaohua Liu
DOI:10.1055/s-2007-992412
日期:2008.1
A C 2-symmetric para-orientation bisprolinamide catalyst has been designed to effectively promote the enantioselective coupling reactions of aldehydes, which delivered the systematic investigation on amine-amide catalysis. Transforming the monoprolinamide 1a into the bisprolinamide 2a improved not only the stereoselectivities but also the reactivities. With this strategy, the functionalized β-hydroxyaldehydes could be furnished in high yields (up to 99%) with good selectivities (up to 8:92 syn/anti and 99% ee) even in the presence of 5 mol% of catalyst 2a. Based on the preliminary experiment and the absolute configuration of cross-aldol adduct, a rational transition state A was proposed to explain the origin of reactivity and selectivity.
设计了一种 C 2 对称对位双脯氨酰胺催化剂,可有效促进醛的对映选择性偶联反应,从而实现了对胺酰胺催化的系统研究。将单丙琳酰胺 1a 转化为双丙琳酰胺 2a 不仅提高了立体选择性,还提高了反应活性。采用这种策略,即使在 5 摩尔催化剂 2a 的存在下,也能以高产率(高达 99%)和良好的选择性(高达 8:92 syn/anti 和 99% ee)制备出官能化的δ-羟基醛。根据初步实验和交叉醛醇加合物的绝对构型,提出了一种合理的过渡态 A 来解释反应性和选择性的起源。