Sequential enantiodivergent organocatalysis: reversibility in enantioswitching controlled by a conformationally flexible guanidine/bisthiourea organocatalyst
作者:Yoshihiro Sohtome、Takahisa Yamaguchi、Shinji Tanaka、Kazuo Nagasawa
DOI:10.1039/c3ob27479a
日期:——
Here we describe our studies on solvent-dependent enantiodivergent Mannich-type reactions utilizing conformationally flexible guanidine/bisthiourea organocatalyst (S,S)-1. Our mechanistic investigations revealed that the stereo-determining steps in both the (R)- and (S)-selective Mannich-type reactions are governed by the cooperative effect of guanidine and thiourea in the inherently monomeric structure
在这里,我们描述了我们利用构象柔性对溶剂依赖性对映体曼尼希型反应的研究 胍/双硫脲有机催化剂(S,S)-1。我们的机理研究表明,(R)-和(S)-选择性曼尼希型反应中的立体确定步骤均受氯乙烯的协同作用支配。胍 和 硫脲(S,S)-1固有的单体结构。基于(R)-和(S)-选择性曼尼希型反应之间的机理相似性,我们发现(S,S)-1催化的反应在混合溶剂体系中显示出独特的可逆性。我们着重介绍了使用(S,S)-1进行顺序对映体有机催化的发展,该方法允许单烧瓶操作和高原位可调性进行对映体转换。