Sun Rui, Ruccolo Serge, Nascimento Daniel L, Qin Yangzhong, Hibbert Nathaniel, Nocera Daniel G
Department of Chemistry and Chemical Biology, Harvard University 12 Oxford Street Cambridge MA 02138 USA
Chem Sci. 2023 Nov 2;14(47):13776-13782. doi: 10.1039/d3sc04362b. eCollection 2023 Dec 6.
The triplet excited states of ketones are found to effect selective H-atom abstraction from strong amide N-H bonds in the presence of weaker C-H bonds through a proton-coupled electron transfer (PCET) pathway. This chemoselectivity, which results from differences in ionization energies (IEs) between functional groups rather than bond dissociation energies (BDEs) arises from the asynchronicity between electron and proton transfer in the PCET process. We show how this strategy may be leveraged to achieve the intramolecular anti-Markovnikov hydroamidation of alkenes to form lactams using camphorquinone as an inexpensive and sustainable photocatalyst.
研究发现，酮的三重激发态可通过质子耦合电子转移（PCET）途径，在存在较弱C-H键的情况下，选择性地从强酰胺N-H键中夺取氢原子。这种化学选择性源于官能团之间电离能（IEs）的差异，而非键解离能（BDEs），它是由PCET过程中电子和质子转移的不同步性产生的。我们展示了如何利用这一策略，以樟脑醌作为廉价且可持续的光催化剂，实现烯烃的分子内反马氏氢酰胺化反应，从而形成内酰胺。
