Homochiral Interpenetrated Frameworks for Photocatalytic β-Functionalization of Saturated Aldehydes

【摘要】：Catalytic synthesis methods that work under ambient atmosphere with benign reaction environments and clean energy have been a major goal in synthetic chemistry[1].The carbonyls as powerful building blocks play a pivotal role in broad areas of synthetic organic chemistry.Compared with theα-carbonyl substitution,the directβ-activation of saturated carbonyls has proven to be a more cumbersome and challenging task owing to the typically unreactiveβ-C(sp~3)-H bonds and other competitive reactions[2].Recently,MacMillan et al.reported a powerful 5ne-carbonyl activation mode to enable directβ-position bonding of saturated aldehydes via a homogeneous photocatalytic approach with dual photoredox organocatalysis system[3].However,in heterogeneous systems,owing the fixed catalytic sites,the modification of electron transfer pathways is more important to control the regioselectivity of photochemicalβ-carbonyl transformations.Herein,we reported the first example of heterogeneous photocatalyticβ-functionalization of saturated aldehydes via modifying electron transfer with a framework interpentration strategy.The appropriate adjustment of the interactions between catalytic centers through the interpenetration of two homochiral MOFs incorporating the inexpensive organic photoredox group and asymmetric organocatalytic group,allows the proximity between the photoredox sites and the asymmetric organocatalytic sites being closer,which greatly increases theβ-carbonyl functionalization transformation and at the same time enhances the the regioselectivity and enantioselectivity of theβ-activation products(Figure 1).