The direct functionalization of allylic C-H bonds is distinguished by enabling rapid assembly of structural complexity from simple molecules.Although Pd-catalyzed allylic C-H functionalization has been extensively stu...The direct functionalization of allylic C-H bonds is distinguished by enabling rapid assembly of structural complexity from simple molecules.Although Pd-catalyzed allylic C-H functionalization has been extensively studied,the discovery of new catalytic systems remains fairly underdeveloped.Here,we disclose a Pt-catalyzed allylic C-H alkylation of a wide range of α-alkenes by using phosphoramidites as ligands and malononitriles as alkylating reagents.Notably,the combination of chiral ureacatalyzed Michael addition and Pt-catalyzed allylic C-H alkylation can serve as an efficient protocol to access chiral tetrahydropyran with high levels of diastereo-and enantioselectivity.Mechanistic studies suggest that the Pt-catalyzed allylic C-H activation proceeds through a concerted proton and two-electron transfer process,which is analogous to transition state geometries of Pd catalysis.展开更多
基金The financial support from the National Nature Science Foundation of China(NSFC)(nos.21831007 and 21672197 for L.-Z.G.and nos.21702182 and 21873081 for X.H.)the Chinese Academy of Sciences(grant no.XDB20020000)+1 种基金Youth Innovation Promotion Association CAS,Fundamental Research Funds for the Central Universities(no.2020XZZX002-02 for X.H.)the State Key Laboratory of Clean Energy Utilization(no.ZJUCEU2020007 for X.H.)is gratefully acknowledged.
文摘The direct functionalization of allylic C-H bonds is distinguished by enabling rapid assembly of structural complexity from simple molecules.Although Pd-catalyzed allylic C-H functionalization has been extensively studied,the discovery of new catalytic systems remains fairly underdeveloped.Here,we disclose a Pt-catalyzed allylic C-H alkylation of a wide range of α-alkenes by using phosphoramidites as ligands and malononitriles as alkylating reagents.Notably,the combination of chiral ureacatalyzed Michael addition and Pt-catalyzed allylic C-H alkylation can serve as an efficient protocol to access chiral tetrahydropyran with high levels of diastereo-and enantioselectivity.Mechanistic studies suggest that the Pt-catalyzed allylic C-H activation proceeds through a concerted proton and two-electron transfer process,which is analogous to transition state geometries of Pd catalysis.
