报告题目：Leveraging high-valent organohalogen for C–H coupling and molecular design
报告时间：2024年9月23日 上午 10:00-11:00
报告地点：16幢一楼路演厅
报 告 人：Alexandr Shafir

邀 请 人：彭勃

报告人简介：
Alexandr Shafir graduated in Chemistry from Hunter College (New York). In 2003, he obtained his PhD in organometallic chemistry from UC Berkeley (USA) under the supervision of John Arnold, with a project involving poly-metallic coordination complexes based on diaminoferrocene. His subsequent postdoctoral stay took place in the Stephen Buchwald laboratory at MIT, where he worked on new catalysts for Cu-catalyzed C-N and C-O bond forming reaction, and, in the process, got a full appreciation of the potential offered by modern organic Method Development. Thanks to the funding through the Ramón y Cajal program, in 2007 he moved to the Universitat Autònoma de Barcelona, where he began work on hypervalent iodine reagents, initially applying them to selective oxidative cross-coupling coupling of unactivated arenes.  Between 2013-2018, Shafir was a Junior Group Leader at the Institut Català d’Investigació Química (ICIQ) in Tarragona. During this time, he established the Synthetic and Mechanistic Research laboratory, which focused on catalysis, MOF-type porous materials, and, once again, oxidative CH functionalization reactions, particularly through the use of hypervalent iodine reagents. To continue this program, in 2018 he was appointed Cientifico Titular (Tenured Scientist) of CSIC at the IQAC institute in Barcelona. Jointly with prof. A. B. Cuenca, he co-founded the BISI Bonds research group, which is currently active in developing new classes of carbon-carbon and carbon-heteroatom bond-forming reaction by combining catalysis and main group chemistry. In particular, over the years the group has been recognized for its contributions to our understanding of the structure and reactivity of high valent iodine reagents, and their applications to modern organic synthesis. Shafir is currently the vice-president of the Catalan section of Spain’s RSEQ (chemical) society.

报告简介：
This talk will focus our group’s recent efforts to discover new reactivity principles and new molecular architectures that leverage the hypervalent halogen(III) center. With respect to reaction discovery, a number of research groups, including that of prof. Bo Peng and our own, have focused on the ability of certain highly reactive λ3-C-I-C, C-I-O and even C-I··N intermediates to undergo a sigmatropic rearrangement. Here, the aromatic iodine(III) acts as a reactivity trampoline to introduce an unsaturated fragment onto the aromatic ring via C–H coupling. Our recent mechanistic insights into this process will be illustrated, with a focus on the versatile iodane-guided ortho C–H allylation reaction, and on the newly developed approach to access remote C–H positions (unpublished). Additionally, the talk will cover our latest findings on the synthesis and properties of new cyclic scaffolds based on two hypervalent halogen atoms, as exemplified by the naphthalene-based bis-λ³iodane dicationic ring 1. Strategies to access hetero-halogen hypervalent I·/·Br and I·/·Cl ring structures will also be presented. Beyond their sheer synthetic challenge, these molecules are an interesting platform for new “angle bar” molecular geometries (provided a near-90o C-I-C angle), and for exploring new classes of inter-halogen synergistic effects.

代表性论文：

1. J. Am. Chem. Soc. 2023, 145, 13796.

2. Angew. Chem. Int. Ed.2020, 59, 16294.

3. Angew. Chem. Int. Ed. 2020, 59, 20201

4. Angew. Chem. Int. Ed.2019, 58, 2617

5. Angew. Chem. Int. Ed.2016, 55, 7152