The spin-center shift (SCS) process, which involves a 1,2-radical translocation and a leaving group elimination, have been extensively explored in the field of C–O bond activation. However, the enantioselective C–O bond cleavage via the SCS process remains a challenge. Herein, we report a dual-catalyst system comprising a phosphoric acid and an organo photocatalyst for enantioselective reductive C–O bond cleavage of 2-N-heteroaryl tetrahydrofurans (THFs) via SCS. Specifically, irradiation of the 2-N-heteroaryl THFs in the presence of chiral spiro phosphoric acid and 4,4′-dichlorobenzophenone resulted in enantioselective reductive cleavage of one C–O bond of the substrate. With this catalyst system, various optically active THFs bearing a quinoline, isoquinoline, or pyridine moiety were obtained with high enantioselectivity. Mechanistic studies indicated that formation of a complex between the substrate and the phosphoric acid increased the reduction potential of the substrate, allowing it to be reduced by the tetrahydrofuran solvent.

中文翻译：

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光诱导电子转移驱动的对映选择性还原 C-O 键裂解


自旋中心偏移 （SCS） 过程涉及 1,2 自由基易位和离基消除，已在 C-O 键激活领域得到广泛探索。然而，通过 SCS 过程进行的对映选择性 C-O 键裂解仍然是一个挑战。在此，我们报道了一种包含磷酸和有机光催化剂的双催化剂系统，用于通过 SCS 对映选择性还原 C-O 键裂解 2-N-杂芳基四氢呋喃 （THF）。具体来说，在手性螺磷酸和 4,4′-二氯二苯甲酮存在下照射 2-N-杂芳基 THF 导致底物的一个 C-O 键的对映选择性还原裂解。使用该催化剂系统，获得了具有高对映选择性的各种带有喹啉、异喹啉或吡啶部分的光学活性 THF。机理研究表明，在底物和磷酸之间形成络合物增加了底物的还原电位，使其能够被四氢呋喃溶剂还原。