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排序方式: 共有2041条查询结果,搜索用时 15 毫秒
1.
Maximilian Stangier Alexej Scheremetjew Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201654
Electrochemical fluorinations of C(sp3)−H bonds with a nucleophilic fluoride source have been accomplished in a chemo- and site-selective fashion, avoiding the use of electrophilic F+ sources and stoichiometric oxidants. The introduced metal-free strategy exhibits high functional group tolerance, setting the stage for late-stage fluorinations of biorelevant motifs. The synthetic utility of the C(sp3)−H fluorination was reflected by subsequent one-pot arylation of the generated benzylic fluorides. 相似文献
2.
Joachim Loup Uttam Dhawa Fabio Pesciaioli Joanna Wencel‐Delord Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2019,58(37):12803-12818
Molecular syntheses largely rely on time‐ and labour‐intensive prefunctionalization strategies. In contrast, C?H activation represents an increasingly powerful approach that avoids lengthy syntheses of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, and crop protection, among others. The enantioselective functionalization of omnipresent C?H bonds has emerged as a transformative tool for the step‐ and atom‐economical generation of chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium and rhodium catalysts. Indeed, despite significant achievements, the use of inexpensive and sustainable 3d metals in asymmetric C?H activations is still clearly in its infancy. Herein, we discuss the remarkable recent progress in enantioselective transformations via organometallic C?H activation by 3d base metals up to April 2019. 相似文献
3.
Aysun apc Mlanie M. Lorion Hui Wang Nina Simon Maria Leidenberger Mariana C. BorgesSilva Diogo R. M. Moreira Yongping Zhu Yuqing Meng Jia Yun Chen Yew Mun Lee Oliver Friedrich Barbara Kappes Jigang Wang Lutz Ackermann Svetlana B. Tsogoeva 《Angewandte Chemie (International ed. in English)》2019,58(37):13161-13161
4.
Torben Rogge Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2019,58(44):15640-15645
Experimental and computational studies provide detailed insight into the selectivity‐ and reactivity‐controlling factors in bifurcated ruthenium‐catalyzed direct C?H arylations and dehydrogenative C?H/C?H functionalizations. Thorough investigations revealed the importance of arene‐ligand‐free complexes for the formation of biscyclometalated intermediates within a ruthenium(II/IV/II) mechanistic manifold. 相似文献
5.
Long Yang Ralf Steinbock Alexej Scheremetjew Rositha Kuniyil Lars H. Finger Antonis M. Messinis Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2020,59(27):11130-11135
A ruthenium‐catalyzed electrochemical dehydrogenative annulation reaction of imidazoles with alkynes has been established, enabling the preparation of various bridgehead N‐fused [5,6]‐bicyclic heteroarenes through regioselective electrochemical C?H/N?H annulation without chemical metal oxidants. Novel azaruthenabicyclo[3.2.0]heptadienes were fully characterized and identified as key intermediates. Mechanistic studies are suggestive of an oxidatively induced reductive elimination pathway within a ruthenium(II/III) regime. 相似文献
6.
Yiyi Weng Xingxing Ding Joo C. A. Oliveira Xiaobin Xu Nikolaos Kaplaneris Meijie Zhu Hantao Chen Zhuo Chen Lutz Ackermann 《Chemical science》2020,11(34):9290
There is a strong demand for novel native peptide motifs for post-synthetic modifications of peptides without pre-installation and subsequent removal of directing groups. Herein, we report an efficient method for peptide late-stage C(sp3)–H arylations assisted by the unmodified side chain of asparagine (Asn) without any exogenous directing group. Thereby, site-selective arylations of C(sp3)–H bonds at the N-terminus of di-, tri-, and tetrapeptides have been achieved. Likewise, we have constructed a key building block for accessing agouti-related protein (AGRP) active loop analogues in a concise manner.An efficient method for peptide late-stage C(sp3)-H arylations assisted by unmodified side chain of asparagine (Asn) without any exogenous directing group has been reported. 相似文献
7.
Most p-block metal amides irreversibly react with metal alkoxides when subjected to alcohols, making reversible transformations with OH-substrates a challenging task. Herein, we describe how the combination of a Lewis acidic square-planar-coordinated aluminum(iii) center with metal–ligand cooperativity leverages unconventional reactivity toward protic substrates. Calix[4]pyrrolato aluminate performs OH-bond activation of primary, secondary, and tertiary aliphatic and aromatic alcohols, which can be fully reversed under reduced pressure. The products exhibit a new form of metal–ligand cooperative amphoterism and undergo counterintuitive substitution reactions of a polar covalent Al–O bond by a dative Al–N bond. A comprehensive mechanistic picture of all processes is buttressed by isolation of intermediates, spectroscopy, and computation. This study delineates how structural constraints can invert thermodynamics for seemingly simple addition reactions and invert common trends in bond energies.The combination of structural constraint and metal–ligand cooperativity in calix[4]pyrrolato aluminate inverts common trends of bond energies and enables reversible OH-bond activation. 相似文献
8.
9.
Late‐Stage Peptide Diversification by Bioorthogonal Catalytic CH Arylation at 23 °C in H2O 下载免费PDF全文
Dr. Yingjun Zhu Michaela Bauer Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):9980-9983
The step‐economical late‐stage diversification of tryptophan‐containing peptides was accomplished through chemo‐ and site‐selective palladium‐catalyzed C?H arylation under exceedingly mild reaction conditions. Thus, the C?H functionalization occurred efficiently at 23 °C with a catalyst loading as low as 0.5 mol %, and/or in H2O. 相似文献