You-Wu Wen

Bio: You-Wu Wen is an academic researcher from Xihua University. The author has contributed to research in topics: Chemistry & Acinetobacter baumannii. The author has an hindex of 1, co-authored 2 publications receiving 1 citations.

Recent Advances in Catalytic Atroposelective Construction of Pentatomic Heterobiaryl Scaffolds

Abstract: Pentatomic heterobiaryl performs as a key structural motif in various natural products and bioactive compounds. With the rapid growth of asymmetric catalysis, five‐membered heterobiaryl‐based catalysts and ligands have emerged as an efficient complementary toolbox for asymmetric catalysis. Therefore, the development of enantioselective construction of such pentatomic atropisomers has received significant attention in recent decade. Various catalytic asymmetric strategies have been established, including central to axial chirality conversion, direct generation of heteroaryl, direct assembly of aryl‐heteroaryls, functionalization of racemic or prochiral biaryls, and chirality transfer from atropisomeric alkenes. Hundreds of unprecedented pentatomic atropisomers have proliferated. Importantly, a few promising axially chiral catalysts and ligands have been obtained from the prepared heterobiaryls after simple transformations. Hence, recent advances of catalytic asymmetric construction of axially chiral pentatomic heterobiaryls through asymmetric catalysis are summarized in this review, involving their scope, mechanism, transformations, and applications.

Highly stereoselective dearomative [3 + 2] cycloadditon of cyclic pyridinium ylides to access spiro-indolizidine scaffolds

Abstract: Spiro-indolizidine scaffolds are attractive structural motifs in natural alkaloids and pharmaceuticals. Herein, we described a highly stereoselective dearomative [3 + 2] cycloaddition between cyclic pyridinium ylides and nitroolefins. A novel type of cyclic pyridinium salts, which bear an electron-withdrawing group on the pyridine ring, have been developed as the ylide precusors and successfully applied in this cyclization. This protocol features a series of advantages inculding broad substrate scope, mild conditions, short reaction time and high level of yield and stereoselectivity, thus providing a concise and efficient method for the construction of spiro-indolizidine scaffolds.

Diastereoselective Synthesis of Dihydrobenzofuran-Fused Spiroindolizidines via Double-Dearomative [3 + 2] Cycloadditions.

Abstract: Spiroindolizidine oxindoles represent a kind of privileged scaffold in many biologically active natural alkaloids. 2,3-Dihydrobenzofuran derivatives exhibit significant bioactivities in a variety of pharmaceuticals. Herein, we assembled these two privileged fragments into a small molecule via double-dearomative [3 + 2] cycloadditions with pyridinium ylides and 2-nitrobenzofurans. This protocol features remarkable advantages including wide substrate scope, mild condition, high level of diastereoselectivities and yields. Thus, a collection of spiroindolizidine-fused dihydrobenzofurans/indolines were facilely produced efficiently.

Catalytic Asymmetric Synthesis of Axially Chiral 3,3'‐Bisindoles by Direct Coupling of Indole Rings

Abstract: A new strategy for the enantioselective synthesis of axially chiral 3,3'-bisindoles was devised by the direct coupling of two indole rings. This strategy makes use of the C3-umpolung reactivity of 2-indolylmethanols, which enables the catalytic asymmetric addition reaction of 2-indolylmethanols with rationally designed 2-substituted indoles, thus constructing axially chiral 3,3'-bisindole scaffolds in overall excellent yields (up to 98%) with high enantioselectivities (up to 96 : 4 er). This approach not only has overcome the challenges in constructing axially chiral five-five-membered heterobiaryls, but also represents a new application of the C3-umpolung reactivity of 2-indolylmethanols in asymmetric catalysis. More importantly, this class of axially chiral 3,3'-bisindoles can undergo a variety of post-functionalizations to give axially chiral 3,3'-bisindole-based organocatalysts, which have found their preliminary applications in asymmetric catalysis. Appendix S1: Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Asymmetric synthesis of N–N axially chiral compounds <i>via</i> organocatalytic atroposelective <i>N</i>-acylation

Abstract: Compared with the well-developed C-C and C-N axial chirality, the asymmetric synthesis of N-N axial chirality remains elusive and challenging. Herein we report the first atroposelective N-acylation reaction of quinazolinone type benzamides with cinnamic anhydrides for the direct catalytic synthesis of optically active atropisomeric quinazolinone derivatives. This reaction features mild conditions and a broad substrate scope and produces N-N axially chiral compounds with high yields and very good enantioselectivities. Besides, the synthetic utility of the protocol was proved by a large scale reaction, transformation of the product and the utilization of the product as an acylation kinetic resolution reagent. Moreover, DFT calculations provide convincing evidence for the interpretation of stereoselection.

Atropisomers with Axial and Point Chirality: Synthesis and Applications.

Abstract: ConspectusEnantiopure atropisomers have become increasingly important in asymmetric synthesis and catalysis, pharmaceutical science, and material science since the discovery of inherent features of axial chirality originating from rotational restriction. Despite the advances made in this field to date, it remains highly desirable to construct structurally diverse atropisomers with potentially useful functions. We propose superposition to match axial and point chirality as a potentially useful strategy to access structurally complex and diverse building blocks for organic synthesis and pharmaceutical science because merging atropisomeric backbones with one or more extra chiral elements can topologically broaden three-dimensional environments to create complex scaffolds with multiple tunable parameters. Over the past decade, we have successfully implemented a strategic design for the superposition of axial and point chirality to develop a series of enantiopure atropisomers and have utilized the synergistic functions of these molecules to enhance chirality transfer in various catalytic asymmetric transformations.In this Account, we present several novel atropisomers with superposed axial and point chirality developed in our laboratory. In our studies, this superposition strategy was used to design and synthesize both biaryl and non-biaryl atropisomers from commercially available chiral sources. Consequently, these atropisomers were used to demonstrate the importance of the synergetic functions of axial and point chirality in specific enantioselective reactions. For example, aromatic amide-derived atropisomers, simplified as Xing-Phos arrays, were broadly employed in Ag-catalyzed [3 + 2] cycloaddition by a series of reactions of aldiminoesters with activated alkenes and imines, as well as being used as chiral solvating agents for the discrimination of optically active mandelic acid derivatives. Considering the powerful potential of non-biaryl atropisomers for asymmetric catalysis, we also explored the transition-metal-catalyzed enantioselective construction of a novel backbone of non-biaryl atropisomers (Ar-alkene, Ar-N axis) bearing both axial and point chirality for the design and synthesis of chiral ligands and functional molecules.The studies presented herein are expected to stimulate further research efforts on the development of functional atropisomers by superposition of matching axial and point chirality. In addition to tunable electron and stereohindrance effects, the synergy between matching chiral elements of axial/point chirality and functional groups is proven to be a special function that cannot be ignored for promoting reactivity and chirality-transfer efficiency in enantioselective synthesis. Consequently, our novel types of scaffolds with superposed axial and point chirality that are capable of versatile coordination with various metal catalysts in asymmetric catalysis highlight the power of the superposition of matching axial and point chirality for the construction of synthetically useful atropisomers.

Organocatalytic Enantioselective Synthesis of Axially Chiral N,N'-Bisindoles.

Abstract: This study establishes the first organocatalytic enantioselective synthesis of axially chiral N,N'-bisindoles via chiral phosphoric acid-catalyzed formal (3+2) cycloadditions of indole-based enaminones as novel platform molecules with 2,3-diketoesters, where de novo indole-ring formation is involved. Using this new strategy, various axially chiral N,N'-bisindoles were synthesized in good yields and with excellent enantioselectivities (up to 87% yield and 96% ee). More importantly, this class of axially chiral N,N'-bisindoles exhibited some degree of cytotoxicity toward cancer cells and was derived into axially chiral phosphine ligands with high catalytic activity. This study provides a new strategy for enantioselective synthesis of axially chiral N,N'-bisindoles using asymmetric organocatalysis and is the first to realize the applications of such scaffolds in medicinal chemistry and asymmetric catalysis.