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Acta Chimica Sinica >

2025 , Vol. 83 >Issue 9: 981 - 986

DOI: https://doi.org/10.6023/A25050159

Communication

An Ether α-C—H Oxidation/Polyene Cyclization Cascade: A Strategy for the Synthesis of Oxatricyclic Scaffolds★

  • Hengxinyu Zuo ,
  • Yaguang Hu ,
  • Xia Qiao ,
  • Ye Zhang , * ,
  • Shaohua Wang , *
Expand
  • State Key Laboratory of Applied Organic Chemistry, School of Pharmacy, Lanzhou University, Lanzhou 730000
* E-mail: ;

† These authors contributed equally to this work.

★ For the VSI “Rising Stars in Chemistry”.

Received date: 2025-05-11

  Online published: 2025-06-30

Supported by

National Key R&D Program of China(2023YFA1506404)

National Natural Science Foundation of China(22371100)

National Natural Science Foundation of China(22401123)

Science and Technology Program of Gansu Province(23ZDFA003)

Science and Technology Program of Gansu Province(24ZDFA003)

Science and Technology Program of Gansu Province(22ZD6FA006)

Science and Technology Program of Gansu Province(23ZDFA015)

Science and Technology Program of Gansu Province(24ZD13FA017)

Science and Technology Program of Gansu Province(24JRRA941)

Science and Technology Program of Gansu Province(23JRRA1144)

Science and Technology Program of Gansu Province(23JRRA1028)

Lanzhou Science and Technology Planning Project(2023-QN-18)

Lanzhou Science and Technology Planning Project(2023-1-17)

Lanzhou Science and Technology Planning Project(2024-1-17)

Fundamental Research Funds for the Central Universities(lzujbky-2023-ct02)

Fundamental Research Funds for the Central Universities(lzujbky-2023-pd08)

Fundamental Research Funds for the Central Universities(lzujbky-2024-17)

Fold

Abstract

The development of efficient and general strategies for the construction of polycyclic architectures remains a significant challenge in medicinal chemistry and organic synthesis. In this work, a tandem α-C—H oxidation/polyene cyclization of acyclic ethers that enables the efficient synthesis of a series of fused oxatricyclic 6/6/6 ring systems is developed. This strategy proceeds via the in situ generated highly reactive oxonium ion intermediate, which is selectively intercepted through intramolecular trapping, allowing for the rapid conversion of simple linear ether precursors into complex polycyclic frameworks. Systematic optimization of reaction conditions revealed that the transformation proceeded under mild conditions with broad substrates scope and excellent functional groups tolerance. Under an argon atmosphere, polyenyl acyclic ethers 1 (1.0 equiv.), zinc bromide (10 mol%), T＋BF4− (2.0 equiv.) and 4Å activated molecular sieve were added to a reaction tube. Subsequently, 1.0 mL of anhydrous 1,2-dichloroethane (DCE) was added as the solvent. The reaction mixture was heated in an oil bath at 70 ℃ for 4 h. Upon completion, the reaction was quenched with saturated aqueous sodium thiosulfate. Then the mixture was extracted with dichloromethane. The organic layers were combined and concentrated under reduced pressure to afford the crude product. The residue was purified by silica gel column chromatography to obtain the cyclized fused oxa-6/6/6-tricyclic architectures 2. Under the optimized conditions, the effects of the ether α-site substituent and terminating aromatic group on the tandem cyclization process were systematically investigated. Remarkably, all substrates underwent efficient cyclization to furnish tricyclic frameworks containing three contiguous stereocenters, achieving yields ranging from moderate to excellent. Notably, the reaction maintained outstanding stereoselectivity, delivering dr>20∶1 in every case examined. According to the proposed mechanism, the specific conformation and the configuration of alkene of key intermediates, combined with the defined geometry of the polyene moiety, induce a highly stereospecific intramolecular cyclization, thereby achieving the efficient diastereoselectivities.

Key words： C—H oxidation; polyene cyclization; oxonium ion; oxatricyclic framework; tandem reaction

Cite this article

Hengxinyu Zuo , Yaguang Hu , Xia Qiao , Ye Zhang , Shaohua Wang . An Ether α-C—H Oxidation/Polyene Cyclization Cascade: A Strategy for the Synthesis of Oxatricyclic Scaffolds★[J]. Acta Chimica Sinica, 2025 , 83(9) : 981 -986 . DOI: 10.6023/A25050159

1 引言

含氧多环化合物因其独特的分子结构和多样的生物活性, 在天然产物与药物研发中占据重要地位[1-6]. 尤其值得关注的是具有稠合氧杂6/6/6三环骨架的分子体系(图1), 该结构不仅广泛存在于甾体和萜类等活性分子中, 更在诸多药物先导化合物中展现核心药效团功能. 例如: 复杂笼状分子cephanolides A~D是2017年岳建民等[7]从粗榧中分离提取的四种结构独特的三尖杉属二萜, 其不对称全合成由翟宏斌课题组[8]于2022年完成, 这类天然产物属于目前报道中结构特征较为罕见的含苯环三尖杉属降二萜. 其中cephanolides A~C是C18降二萜类化合物; 化合物euphorlactone A于2023年从中药狼毒大戟中分离得到, 对乙酰胆碱酯酶(AChE)有明显的抑制作用, 凸显其作为药物前体的潜力[9]; 从墨西哥鼠尾草中提取的主要活性成分salvinorin A, 具有显著的致幻精神活性, 是一种重要的具有κ-阿片受体抑制活性的非含氮天然产物[10]. 这些分子共有的连续手性中心及氧杂多稠环特征, 对其生物活性产生决定性影响, 因此发展该类结构的高效合成策略对相关药物活性分子开发具有重要意义.
图1 代表性含有氧杂三环结构的天然产物

Figure 1 Representative examples of natural products containing oxatricyclic scaffolds

多烯环化反应作为复杂天然产物全合成的一种典型的仿生策略, 其显著优势在于通过一步反应选择性构建多个C—C键, 可同时实现稠合环系的高效构筑与关键立体中心的精准确立. 该策略能够将线性前体分子直接转化为天然产物的核心多环骨架, 凭借其优异的步骤经济性、原子经济性和立体控制特性, 为萜类及生物碱等复杂分子的高效合成提供了创新路径, 因而在当代合成化学领域备受关注. 迄今为止, 在多烯环化领域已经取得了重要进展[11-31], 比如Loh[32]、李昂[33]、赵军锋[34]、丁寒锋[35]、杨震[36]和谢志翔[37]等采用了巧妙的多烯环化策略完成了一系列复杂天然产物的全合成. 近年来王少华课题组[38-43]开展了系统的串联多烯环化研究, 发展了一系列联烯和炔丙醇酯底物引发的多烯环化反应, 高效构建三环骨架的同时在C(2)-C(3)位引入双键, 进而以此反应作为关键步骤完成了松香烷型三环二萜(±)-shonanol消旋体的全合成和对映贝壳杉烷型二萜(－)-erythroxylisin A的不对称全合成(Scheme 1, a). 然而, 现有方法仍面临复杂多烯前体的合成困难、副产物较多及对高张力环系的适用性有限等问题和诸多挑战, 严重制约了其在合成化学领域的应用潜力. 所以, 开发基于新颖前体底物的高效合成方法十分必要.
图式1 基于醚的α-C—H键氧化/多烯环化串联反应

Scheme 1 Tandem α-C—H oxidation/polyene cyclization

醚类化合物作为一类常见易得的化合物, 直接将醚类化合物α位官能团化进而转化为复杂的多环结构的方法将具备独特的合成应用优势[44-46]. 在此, 本文将报道一种以醚类化合物作为原料, 通过醚的α-C—H键氧化原位产生的高活性氧鎓离子引发多烯环化反应, 以${{\text{T}}^{_{}}}\text{BF}_{\text{4}}^{}$作为氧化剂、ZnBr2作为催化剂, 实现了含有连续三个立体中心的稠合氧杂6/6/6三环的高效合成(Scheme 1, b).

2 结果与讨论

2.1 反应条件优化

我们选取化合物1a作为模板底物, InCl3作为催化剂、${{\text{T}}^{_{}}}\text{BF}_{\text{4}}^{}$作为氧化剂、4Å分子筛作为添加剂、二氯乙烷(DCE)作为溶剂的反应条件进行尝试(表1), 能以88%分离收率、>20∶1的dr值得到目标产物2a (Entry 1). 通过筛选Lewis酸发现ZnBr2可以使收率提高到92%, 其它Lewis酸对反应影响较小(Entries 2~4). 常见氧化剂如硝酸铈铵(CAN)、叔丁基过氧化氢(TBHP)、二叔丁基过氧化物(DTBP)、Chloranil和K2S2O8均不能有效促进反应发生(Entries 5~9). 溶剂对反应结果影响较大, CH2Cl2和CHCl3作为溶剂时收率显著降低, 而在甲苯(Toluene)、乙腈(MeCN)、N,N-二甲基甲酰胺(DMF)或二氧六环(1,4-dioxane)中反应却不发生(Entries 10~15). 最后对温度进行了考察, 我们发现, 室温下不能得到目标产物, 当反应温度降低至50 ℃后, 收率明显降低到55%, 而使用更高的温度时可能由于原料的分解, 收率有所下降(Entries 16~18). 最终确定的最佳反应条件是: 1a (0.15 mmol), ${{\text{T}}^{_{}}}\text{BF}_{\text{4}}^{}$ (2.0 equiv.), ZnBr2 (10 mol%), 4Å MS (30 mg), DCE (1.0 mL)在70 ℃反应4 h.
表1 反应条件筛选

Table 1 Screening of reaction conditions

Entry Lewis acid Oxidant Solvent Temp./℃ Yield/% dr
1 InCl3 T＋BF4− DCE 70 88 >20∶1
2 Cu(OAc)2 T＋BF4− DCE 70 85 >20∶1
3 ZnCl2 T＋BF4− DCE 70 81 >20∶1
4 ZnBr2 T＋BF4− DCE 70 92 >20∶1
5 ZnBr2 CAN DCE 70 n.d. —
6 ZnBr2 TBHP DCE 70 n.d. —
7 ZnBr2 DTBP DCE 70 n.d. —
8 ZnBr2 Chloranil DCE 70 n.d. —
9 ZnBr2 K2S2O8 DCE 70 n.d. —
10 ZnBr2 T＋BF4− CH2Cl2 70 70 >20∶1
11 ZnBr2 T＋BF4− CHCl3 70 44 >20∶1
12 ZnBr2 T＋BF4− Toluene 70 n.d. —
13 ZnBr2 T＋BF4− MeCN 70 n.d. —
14 ZnBr2 T＋BF4− DMF 70 n.d. —
15 ZnBr2 T＋BF4− 1,4-Dioxane 70 n.d. —
16 ZnBr2 T＋BF4− DCE r.t. n.d. —
17 ZnBr2 T＋BF4− DCE 50 55 >20∶1
18 ZnBr2 T＋BF4− DCE 90 85 >20∶1

2.2 底物普适性考察

在获得了最佳反应条件后, 对该C—H键氧化/多烯环化串联反应的底物范围进行了考察(表2). 首先考察R1的结构, 当R1为烯烃时, 均能以较好的收率得到对应产物2b, 2c. 随后考察电性效应对反应的影响, 实验结果表明, 原位生成的氧鎓离子的稳定性对串联环化反应的影响较大, 该反应体系对多种关键有机官能团展现出优异的兼容性, 不同电子性质的甲氧基、烷基、卤素及氰基在标准反应条件下均能耐受. 苯环上对位连有富电子取代基时收率明显高于缺电子取代基. 当甲氧基、叔丁基和甲基等给电子基团取代在苯环对位时均能得到较好的收率(2e~2g); 当苯环的对位采用吸电子取代基取代时, 反应产率明显下降(2j), 当苯环对位被卤原子取代时, 同样可以很好地兼容, 化合物2l的X射线单晶进一步确定了环化产物的相对构型. 取代基的位阻效应影响较小, 当甲基分别取代在苯基的邻、间或对位时, 均可以以80%左右的收率得到对应的产物(2g~2i). 随后考察反应终止位置上苯环取代基, 在苯环的对位、间位和邻位取代, 收率依然维持在70%~80%之间. 遗憾的是, 将苯环更换为噻吩时却未能得到目标产物.
表2 底物适用性考察

Table 2 Substrate scope investigation

aThe reactions were conducted with 1 (0.15 mmol), T＋BF4− (2.0 equiv.), ZnBr2 (10 mol%) and 4Å activated molecular sieve (30 mg) in DCE (1.0 mL) at 70 ℃ for 4 h. Isolated yield. dr determined by 1H NMR.

2.3 反应机理推测

为了深入理解反应过程, 根据文献报道[32-43]和实验结果, 我们提出了该反应的可能机理(Scheme 2). 底物1a的醚的α-C—H键在氧化剂作用下生成高活性的氧鎓离子, 随后在Lewis酸催化下发生串联多烯环化反应, 即分子内双键捕获氧鎓离子, 进而发生6-endo-trig环化和傅克反应, 最终生成环化产物2a. 至于此串联多烯环化的非对映选择性高效控制问题, 主要受关键中间体的构象和烯烃双键构型影响, 醚α位的大位阻Ph和烯烃上的Me为交错构象, 其空间位阻效应很小; 根据Stork- Eschenmoser假说[47-48], E式烯烃的多烯环化得到trans-十氢化萘产物. 综上, 这两个因素导致了多烯环化的立体专一性过程.
图式2 可能的反应机理

Scheme 2 Plausible reaction mechanism

3 结论

发展了醚的α-C—H键氧化/多烯环化串联反应, 基于高活性氧鎓离子中间体的高效产生与精准捕获, 合成了含有α-取代环醚的稠合氧杂6/6/6三环化合物. 该方法反应条件温和, 官能团兼容性好, 为复杂含氧三环结构的合成和修饰提供了一个简洁的方法. 此外, 有望通过改造手性路易斯酸或引入手性配体进一步实现对映选择性控制[49-54], 从而扩展该方法在手性多环骨架合成中的应用潜力.

4 实验部分

4.1 底物1的制备

以市售原料3-丁炔-1-醇(3)为起始物, 经炔烃二茂锆化-碘化、叔丁基二甲基硅醚(TBS)保护、Suzuki偶联及选择性脱保护制得关键中间体; 随后通过NaH介导的烷基化反应高效构建系列底物1.

4.2 醚的α-C—H键氧化/多烯环化串联反应

在氩气条件下, 向干燥的反应管中加入系列底物1a~1r (1.0 equiv.)、活化的4Å分子筛(30 mg)、溴化锌(10 mol%)和氧化剂${{\text{T}}^{_{}}}\text{BF}_{\text{4}}^{}$ (2.0 equiv.), 之后加入1.0 mL的超干DCE溶剂, 将反应置于70 ℃的油浴中反应4 h, 通过薄层色谱(石油醚/乙酸乙酯)监测到反应结束后, 以饱和硫代硫酸钠溶液淬灭, 二氯甲烷对该反应体系萃取三次(15 mL×3), 合并有机相, 通过无水Na2SO4干燥, 并于真空下浓缩得粗品, 通过硅胶柱色谱纯化(石油醚/乙酸乙酯, V∶V=20∶1), 最终得到系列环化产物2.
(Zhao, C.)

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]
Mohamad, K.; Sévenet, T.; Dumontet, V.; Paı̈s, M.; Van Tri, M.; Hadi, H.; Awang, K.; Martin, M.-T. Phytochemistry 1999, 51, 1031.

[2]
Masters, K.-S.; Bräse, S. Chem. Rev. 2012, 112, 3717.

[3]
Zhang, J.-S.; Tang, Y.-Q.; Huang, J.-L.; Li, W.; Zou, Y.-H.; Tang, G.-H.; Liu, B.; Yin, S. Phytochemistry 2017, 144, 151.

[4]
Chang, Y.; Meng, F.-C.; Wang, R.; Wang, C.-M.; Lu, X.-Y.; Zhang, Q.-W. Stud. Nat. Prod. Chem. 2017, 53, 339.

[5]
Wang, G.-K.; Zheng, J.; Sun, Y.-P.; Jin, W.-F.; Liu, H.-W.; Yu, Y.; Zhou, Z.-Y.; Liu, J.-S. Phytochem. Lett. 2018, 27, 59.

[6]
Fan, S.; Zhang, C.; Luo, T.; Wang, J.; Tang, Y.; Chen, Z.; Yu, L. Molecules 2019, 24, 3679.

[7]
Fan, Y.-Y.; Xu, J.-B.; Liu, H.-C.; Gan, L.-S.; Ding, J.; Yue, J.-M. J. Nat. Prod. 2017, 80, 3159.

[8]
Qing, Z.; Mao, P.; Wang, T.; Zhai, H. J. Am. Chem. Soc. 2022, 144, 10640.

[9]
Wei, J.; Li, Z.; Shan, M.; Wu, F.; Li, L.; Ma, Y.; Wu, J.; Li, X.; Liu, Y.; Hu, Z.; Zhang, Y.; Wu, Z. Org. Biomol. Chem. 2023, 21, 6949.

[10]
Yan, F.; Mosier, P. D.; Westkaemper, R. B.; Stewart, J.; Zjawiony, J. K.; Vortherms, T. A.; Sheffler, D. J.; Roth, B. L. Biochemistry 2005, 44, 8643.

[11]
Ungarean, C. N.; Southgate, E. H.; Sarlah, D. Org. Biomol. Chem. 2016, 14, 5454.

DOI PMID

[12]
Barrett, A. G. M.; Ma, T.-K.; Mies, T. Synthesis 2019, 51, 67.

[13]
Yao, L.; Gui, J. Chin. J. Org. Chem. 2022, 42, 2703 (in Chinese).

(姚良才, 桂敬汉, 有机化学, 2022, 42, 2703.)

DOI

[14]
Barrett, T. N.; Barrett, A. G. M. J. Am. Chem. Soc. 2014, 136, 17013.

DOI PMID

[15]
Rosen, B. R.; Werner, E. W.; O’Brien, A. G.; Baran, P. S. J. Am. Chem. Soc. 2014, 136, 5571.

[16]
Xu, H.; Tang, H.; Feng, H.; Li, Y. J. Org. Chem. 2014, 79, 10110.

[17]
Rosales, A.; Muñoz-Bascón, J.; Roldan-Molina, E.; Rivas-Bascón, N.; Padial, N. M.; Rodríguez-Maecker, R.; Rodríguez-García, I.; Oltra, J. E. J. Org. Chem. 2015, 80, 1866.

[18]
Fuse, S.; Ikebe, A.; Oosumi, K.; Karasawa, T.; Matsumura, K.; Izumikawa, M.; Johmoto, K.; Uekusa, H.; Shin-ya, K.; Doi, T.; Takahashi, T. Chem.-Eur. J. 2015, 21, 9454.

[19]
Camelio, A. M.; Johnson, T. C.; Siegel, D. J. Am. Chem. Soc. 2015, 137, 11864.

DOI PMID

[20]
Speck, K.; Wildermuth, R.; Magauer, T. Angew. Chem., Int. Ed. 2016, 55, 14131.

[21]
Ting, C. P.; Xu, G.; Zeng, X.; Maimone, T. J. J. Am. Chem. Soc. 2016, 138, 14868.

PMID

[22]
Yang, Z.; Li, S.; Luo, S. Acta Chim. Sinica 2017, 75, 351 (in Chinese).

(杨忠波, 李速家, 罗三中, 化学学报, 2017, 75, 351.)

DOI

[23]
Lin, S.-C.; Chein, R.-J. J. Org. Chem. 2017, 82, 1575.

[24]
Elkin, M.; Szewczyk, S. M.; Scruse, A. C.; Newhouse, T. R. J. Am. Chem. Soc. 2017, 139, 1790.

[25]
Peng, X.-R.; Lu, S.-Y.; Shao, L.-D.; Zhou, L.; Qiu, M.-H. J. Org. Chem. 2018, 83, 5516.

[26]
Ma, T.-K.; Elliott, D. C.; Reid, S.; White, A. J. P.; Parsons, P. J.; Barrett, A. G. M. J. Org. Chem. 2018, 83, 13276.

[27]
Tao, Z.; Robb, K. A.; Zhao, K.; Denmark, S. E. J. Am. Chem. Soc. 2018, 140, 3569.

[28]
Lai, Y.; Zhang, N.; Zhang, Y.; Chen, J.-H.; Yang, Z. Org. Lett. 2018, 20, 4298.

DOI PMID

[29]
Zhou, S.; Guo, R.; Yang, P.; Li, A. J. Am. Chem. Soc. 2018, 140, 9025.

[30]
Chen, X.; Zhang, D.; Xu, D.; Zhou, H.; Xu, G. Org. Lett. 2020, 22, 6993.

[31]
Xue, D.-S.; Xu, M.-M.; Zheng, C.-Y.; Yang, B.-C.; Hou, M.; He, H.-B.; Gao, S.-H. Chin. J. Chem. 2019, 37, 135.

[32]
Li, B.; Lai, Y. C.; Zhao, Y.; Wong, Y. H.; Shen, Z. L.; Loh, T. P. Angew. Chem., Int. Ed. 2012, 51, 10619.

[33]
Deng, J.; Zhou, S.; Zhang, W.; Li, J.; Li, R.; Li, A. J. Am. Chem. Soc. 2014, 136, 8185.

DOI PMID

[34]
Fan, L.; Han, C.; Li, X.; Yao, J.; Wang, Z.; Yao, C.; Chen, W.; Wang, T.; Zhao, J. Angew. Chem., Int. Ed. 2018, 57, 2115.

[35]
Hu, J.; Jia, Z.; Xu, K.; Ding, H. Org. Lett. 2020, 22, 1426.

[36]
Tang, F.; Zhang, Z.-C.; Song, Z.-L.; Li, Y.-H.; Zhou, Z.-H.; Chen, J.-J.; Yang, Z. J. Am. Chem. Soc. 2025, 147, 4731.

DOI PMID

[37]
Li, X.; Chang, Z.; Duan, S.; Xie, Z. Angew. Chem., Int. Ed. 2025, 64, e202416211.

[38]
Zhang, Y.; Bao, W.; Zhang, X.-M.; Zhu, D.-Y.; Wang, S.-H. Org. Biomol. Chem. 2025, 23, 2749.

[39]
Huo, C.-Y.; Zheng, T.-L.; Dai, W.-H.; Zhang, Z.-H.; Wang, J.-D.; Zhu, D.-Y.; Wang, S.-H.; Zhang, X.-M.; Xu, X.-T. Chem. Sci. 2022, 13, 13893.

[40]
Zheng, T.-L.; Huo, C.-Y.; Bao, W.; Xu, X.-T.; Dai, W.-H.; Cheng, F.; Duan, D.-S.; Yang, L.-L.; Zhang, X.-M.; Zhu, D.-Y.; Wang, S.-H. Org. Lett. 2023, 25, 7476.

[41]
Wu, S.; Tang, J.; Zhou, Y.; Xu, X.; Zhang, H.; Wang, S. Chin. J. Org. Chem. 2024, 44, 613 (in Chinese).

(吴思敏, 唐嘉欣, 周于佳, 徐学涛, 张昊星, 王少华, 有机化学, 2024, 44, 613.)

DOI

[42]
Zhang, Y.-T.; Hou, X.-W.; Cheng, F.; Huo, C.-Y.; Li, J.; Xu, X.-T.; Zhu, D.-Y.; Wang, S.-H. Tetrahedron Lett. 2024, 140, 155023.

[43]
Zheng, T.-L.; Liu, S.-Z.; Huo, C.-Y.; Li, J.; Wang, B.-W.; Jin, D.-P.; Cheng, F.; Chen, X.-M.; Zhang, X.-M.; Xu, X.-T.; Wang, S.-H. CCS Chemistry 2021, 3, 2795.

[44]
Jiao, Z.-W.; Tu, Y.-Q.; Zhang, Q.; Liu, W.-X.; Zhang, S.-Y.; Wang, S.-H.; Zhang, F.-M.; Jiang, S. Nat. Commun. 2015, 6, 7332.

[45]
Liu, L.; Cheng, H.-L.; Ma, W.-Q.; Hou, S.-H.; Tu, Y.-Q.; Zhang, F.-M.; Zhang, X.-M.; Wang, S.-H. Chem. Commun. 2018, 54, 196.

[46]
Li, X.-B.; Zhou, C.; Liu, X.-T.; Wang, T.; Yu, X.H.; Ma, H.-M.; Li, C.-Q.; Chin. J. Org. Chem. 2019, 39, 2906.

[47]
Stork, G.; Burgstahler, A. W. J. Am. Chem. Soc., 1955, 77, 5068.

[48]
Eschenmoser, A.; Ruzicka, L.; Jeger, O.; Arigoni, D. Helv. Chim. Acta 1955, 38, 1890.

[49]
Kang, T.-F.; Ge, S.-L.; Lin, L.-L.; Lu, Y.; Liu, X. -H.; Feng, X.-M. Angew. Chem., Int. Ed. 2016, 55, 5541.

[50]
L, J.; Zhou, L.-J.; Wang, C.; Liang, D.-M.; Li, Z.-M.; Zou, Y.; Wang, Q.-R.; Goeke, A. Chem.-Eur. J. 2016, 22, 6258.

[51]
Wang, G.-P.; Chen, M.-Q.; Zhu, S.-F.; Zhou, Q.-L. Chem. Sci. 2017, 8, 7197.

[52]
Cao, J.; Hu, M.-Y.; Liu, S.-Y.; Zhang, X.-Y.; Zhu, S.-F.; Zhou, Q.-L. J. Am. Chem. Soc. 2021, 143, 6962.

[53]
Pellissier, H. Coord. Chem. Rev. 2021, 439, 213926.

[54]
Zhan, T.-Y.; Yang, L.-K.; Chen, Q.-Y.; Weng, R.; Liu, X.-H.; Feng, X.-M. CCS Chem. 2023, 5, 2101.

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