设计,合成,描述了氨基官能化卟啉作为一类新型不对称有机光催化双功能催化剂的初步研究。衍生自5,10,15,20-四苯基卟啉(TPPH2)的两种新型胺-卟啉杂种,其中环状仲胺部分共价连接到β-吡咯位置(A型)或内消旋苯基之一的对位(B型),是通过冷凝制备的,还原胺化,或由合适的卟啉(甲酰基或甲胺衍生物)与容易获得的手性胺的酰胺化反应。对A型胺-卟啉杂种作为不对称的可能使用的初步研究,双官能有机光催化剂是使用手性,咪唑啉酮催化的环戊二烯28和反式肉桂醛29之间的Diels-Alder环加成反应作为基准。这个过程的产量和立体化学结果,在纯有机催化条件下获得,在双重有机催化下,在双功能有机光催化下,进行了比较。
The design, synthesis, and initial
study of amino-functionalized porphyrins as a new class of bifunctional catalysts for asymmetric organophotocatalysis is described. Two new types of amine-porphyrin hybrids derived from 5,10,15,20-tetraphenylporphyrin (TPPH2), in which a cyclic secondary amine moiety is covalently linked either to a β-pyrrolic position (Type A) or to the p-position of one of the meso phenyl groups (Type B), were prepared by condensation, reductive amination, or amidation reactions from the suitable porphyrins (either formyl or methanamine derivatives) with readily available chiral amines. A preliminary
study of the possible use of Type A amine-porphyrin hybrids as asymmetric, bifunctional organophotocatalysts was performed using the chiral, imidazolidinone-catalyzed Diels-Alder cycloaddition between cyclopentadiene 28 and trans-cinnamaldehyde 29 as a benchmark reaction. The yield and the stereochemical outcome of this process, obtained under purely organocatalytic conditions, under dual organophocatalysis, and under bifunctional organophotocatalysis, were compared.