Izquierdo Cristina, Esteban Francisco, Parra Alejandro, Alfaro Ricardo, Alemán José, Fraile Alberto, Ruano José Luis García
Departamento de Química Orgánica (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid , 28049 Madrid, Spain.
J Org Chem. 2014 Nov 7;79(21):10417-33. doi: 10.1021/jo5018519. Epub 2014 Oct 24.
1,3-Dipolar cycloadditions of C,N-cyclic azomethine imines with α,β-unsaturated aldehydes can be performed with complete control of the regio-, exo-, and enantioselectivity under aminocatalytic conditions. The so far never studied competence of the iminium-dienamine reactivity inherent to β-alkyl α,β-unsaturated aldehydes was studied, which was possible by allowing achievement of complete control of the chemoselectivity in reactions of the β-arylmethyl derivatives with azomethine imines by using different additives and organocatalysts, whose role has been rationalized by DFT calculations and chemical proofs. Thus, it has been possible to selectively obtain the pyrazolidines resulting from both the attack to the C2-C3 (via iminium) and the C3-C4 (via dienamine) bonds at the starting enals, which can be used as precursors of interesting tetrahydroisoquinolinic compounds.
在氨基催化条件下，C,N-环状偶氮甲碱亚胺与α,β-不饱和醛的1,3-偶极环加成反应能够完全控制区域选择性、外型选择性和对映选择性。对β-烷基α,β-不饱和醛固有的亚胺离子-二烯胺反应活性进行了迄今从未研究过的研究，通过使用不同的添加剂和有机催化剂，在β-芳基甲基衍生物与偶氮甲碱亚胺的反应中实现对化学选择性的完全控制，从而使这一研究成为可能，其作用已通过密度泛函理论计算和化学证据得到合理解释。因此，有可能选择性地获得起始烯醛中C2-C3（通过亚胺离子）和C3-C4（通过二烯胺）键进攻所产生的吡唑烷，这些吡唑烷可用作有趣的四氢异喹啉化合物的前体。
