of main observation and conclusion A new class of axially chiral aryl-alkene-indole frameworks have been designed, and the first catalytic asymmetric construction of such scaffolds has been established by the strategy of organocatalytic (Z/E)-selective and enantioselective (4+3) cyclization of 3-alkynyl-2-indolylmethanols with 2-naphthols or phenols (all >95 : 5 E/Z, up to 98% yield, 97% ee). This reaction also represents the first catalytic asymmetric construction of axially chiral alkene-heteroaryl scaffolds, which will add a new member to the atropisomeric family. This approach has not only confronted the great challenges in constructing axially chiral alkene-heteroaryl scaffolds but also provided a powerful strategy for the enantioselective construction of axially chiral aryl-alkene-indole frameworks.
of main observation and conclusion A new class of indole-based allylic donors have been designed and developed for palladium-catalyzed decarboxylative allylations. In addition, the first application of these indole-based allylic donors in palladium-catalyzed decarboxylative [3+2] cycloaddition and allylic amination has been achieved by reacting with isocyanates and sulfonyl amines, respectively. This approach represents the first design of indole-based allylic donors, which is helpful for settling the challenge of designing and developing new class of heterocycle-based allylic donors for Pd-catalyzed decarboxylative allylation reactions. Moreover, the application of this new class of allylic donors in cycloadditions and substitutions will add new contents to the research field of decarboxylative allylation.
Orbital Angular Momentum Beams
In article number 2200118, Peng Chen, Yan‐Qing Lu, and colleagues report a robust method for orbital angular momentum (OAM) beam tailoring in 3D space via preprogrammed liquid crystals. 3D OAM beam lattices with volumetric identical or space‐variant OAM modes are generated efficiently in a spin‐controllable and electrically‐tunable manner. This opens a promising avenue for OAM harnessing with both large capacity and good flexibility.
The regio‐ and enantioselective (3+3) cycloaddition of nitrones with 2‐indolylmethanols was accomplished by the cooperative catalysis of hexafluoroisopropanol (HFIP) and chiral phosphoric acid (CPA). Using this approach, a series of indole‐fused six‐membered heterocycles were synthesized in high yields (up to 98 %), with excellent enantioselectivities (up to 96 % ee) and exclusive regiospecificity. This approach enabled not only the first organocatalytic asymmetric (3+3) cycloaddition of nitrones but also the first C3‐nucleophilic asymmetric (3+3) cycloaddition of 2‐indolylmethanols. More importantly, theoretical calculations elucidated the role of the cocatalyst HFIP in helping CPA control the reactivity and enantioselectivity of the reaction, demonstrating a new mode of cooperative catalysis.
Axially chiral indole‐based frameworks have been recognized as a class of important five‐membered heterobiaryls and developing catalytic asymmetric approaches for constructing these frameworks in an enantioselective manner is highly desirable. In recent years, synthetic chemists have paid much attention to this research field, and rapid developments have occurred. This article summarizes the rapid advances in this field and gives some insights into future developments, which will help this research field to thrive. For more information, see the Minireview by W. Tan, F. Shi et al. on page 15779.
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