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The Nazarov cyclization reaction is a convenient, widely used method for the synthesis of cyclopentenones. In this account, we reviewed our recent efforts on the chiral proton-transfer shuttle catalysts promoted enantioselective Nazarov cyclization. We have synthesized various chiral cyclopenta[ b ]indoles and chiral α,α′-disubstituted cyclopentenones by means of cooperative catalysis of a Lewis acid and a chiral spiro phosphoric acid. The mechanistic studies revealed that the chiral spiro phosphoric acid acts as a multifunctional catalyst: it co-catalyzes the cyclization of the dienone and enantioselectively catalyzes a proton-transfer reaction of the enol intermediate via a hydrogen--bonding network. 1 Introduction 2 Enantioselective Nazarov Cyclization of Indole Enones 3 Enantioselective Silicon-Directed Nazarov Cyclization 4 Conclusion [ABSTRACT FROM AUTHOR]

A protocol for iodine‐catalyzed oxidative rearrangement of tertiary and secondary amines has been developed. This metal‐free protocol provides an atom‐economical, efficient access to synthetically useful α‐amino acid derivatives from readily available acyclic and cyclic tertiary or secondary amines. [ABSTRACT FROM AUTHOR]

A copper-catalyzed Mannich-type oxidative β-functionalization reaction of amines has been developed. In the presence of an oxidant and a copper catalyst, tertiary amines reacted with N-tosylimines, providing synthetically important 1,3-diamines and enamines, respectively. Preliminary mechanistic studies suggested that the oxidation of the tertiary amine to the enamine intermediate triggers subsequent Mannich-type reactions with N-tosylimines and thus enables the direct β-functionalization of the tertiary amines. [ABSTRACT FROM AUTHOR]

As the monomers of proteins, amino acids are critical in chemistry and biology, playing important roles in multiple fields such as synthetic chemistry, medicinal chemistry, and materials chemistry. Unlike proteinogenic amino acids, unnatural amino acids can be difficult to obtain from living organisms and generally are synthesized chemically. Recently, a method involving the asymmetric N−H bond carbene insertion reaction with α‐diazoacetates as the carbene precursor has shown high enantioselectivity and good functional group tolerance, allowing for the facile synthesis of natural and unnatural amino acids and the introduction of new concepts in catalysis. [ABSTRACT FROM AUTHOR]

An iron-catalyzed asymmetric intramolecular cyclopropanation was realized in high yields and excellent enantioselectivity (up to 97 % ee) by using the iron complexes of chiral spiro-bisoxazoline ligands as catalysts. The superiority of iron catalysts exhibited in this reaction demonstrated the potential abilities of this sustainable metal in asymmetric carbenoid transformation reactions. [ABSTRACT FROM AUTHOR]

An iron-catalyzed asymmetric intramolecular cyclopropanation was realized in high yields and excellent enantioselectivity (up to 97 % ee) by using the iron complexes of chiral spiro-bisoxazoline ligands as catalysts. The superiority of iron catalysts exhibited in this reaction demonstrated the potential abilities of this sustainable metal in asymmetric carbenoid transformation reactions. [ABSTRACT FROM AUTHOR]

A highly enantioselective NH insertion reaction of α-diazoketones was developed by using cooperative catalysis by dirhodium(II) carboxylates and chiral spiro phosphoric acids. The insertion reaction provides a new access route to diverse chiral α-aminoketones, which are versatile building blocks in organic synthesis, with fast reaction rates, good yields and high enantioselectivity under mild and neutral conditions. [ABSTRACT FROM AUTHOR]

A highly enantioselective NH insertion reaction of α-diazoketones was developed by using cooperative catalysis by dirhodium(II) carboxylates and chiral spiro phosphoric acids. The insertion reaction provides a new access route to diverse chiral α-aminoketones, which are versatile building blocks in organic synthesis, with fast reaction rates, good yields and high enantioselectivity under mild and neutral conditions. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed asymmetric OH insertion reaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α-aryl-α-diazoacetates into the OH bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium-catalyzed asymmetric OH insertion reaction provided an efficient and highly enantioselective method for the preparation of synthetically useful optically active α-aryl-α-aryloxyacetates. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed asymmetric OH insertion reaction was developed. Palladium complexes with chiral spiro bisoxazoline ligands promoted the insertion of α-aryl-α-diazoacetates into the OH bond of phenols with high yield and excellent enantioselectivity under mild reaction conditions. This palladium-catalyzed asymmetric OH insertion reaction provided an efficient and highly enantioselective method for the preparation of synthetically useful optically active α-aryl-α-aryloxyacetates. [ABSTRACT FROM AUTHOR]

A highly efficient asymmetric hydrogenation of α,β-unsaturated carboxylic acids with tetrasubstituted olefin catalyzed by chiral spiro iridium complexes has been developed for the preparation of chiral α-substituted carboxylic acids in excellent enantioselectivities (up to 99% ee). [ABSTRACT FROM AUTHOR]

Spiral binding: A highly enantioselective hydrogenation of unsaturated heterocyclic acids has been developed by using chiral iridium/spirophosphino oxazoline catalysts (see scheme; BArF−=tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate, Boc=tert‐butoxycarbonyl). This reaction provided an efficient method for the preparation of optically active heterocyclic acids with excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

Iridum hat den Dreh 'raus: Die hoch enantioselektive Titelreaktion setzt auf Iridium ‐ Katalysatoren mit chiralen spirocyclischen Phosphanyloxazolin ‐ Liganden (siehe Schema; BArF−=Tetrakis[3,5 ‐ bis(trifluormethyl)phenyl]borat, Boc=tert ‐ Butoxycarbonyl). Somit ist eine effiziente Herstellungsmethode für optisch aktive heterocyclische Säuren verfügbar. [ABSTRACT FROM AUTHOR]

Abstract: A copper-catalyzed asymmetric allylic oxidation of acyclic olefins has been developed. By using the complexes of copper and chiral spiro bisoxazoline ligands as catalysts, the oxidation of various acyclic olefins was accomplished with excellent regioselectivity (>20:1 in most cases) and up to 67% ee under mild reaction conditions, which represents one of the best results for the enantioselective allylic oxidation of acyclic olefins. [Copyright &y& Elsevier]

Efficient: A copper‐catalyzed enantioselective intramolecular insertion of carbenoids into phenolic OH bonds has been developed. This method can be used for the synthesis of the title compounds in high yields and excellent enantioselectivities under mild and neutral conditions (see scheme). NaBArF=sodium tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate. [ABSTRACT FROM AUTHOR]

Effizient: Eine kupferkatalysierte enantioselektive intramolekulare Insertion von Carbenoiden in phenolische O ‐ H ‐ Bindungen wurde entwickelt. Die Methode wurde für die Synthese der Titelverbindungen in hohen Ausbeuten und mit exzellenten Enantioselektivitäten unter milden und neutralen Bedingungen verwendet. NaBArF=Natriumtetrakis[3,5 ‐ bis(trifluormethyl)phenyl]borat. [ABSTRACT FROM AUTHOR]

Abstract: A selective oxidation of benzylic C(sp3)–H bonds to C(sp3)–O bonds catalyzed by copper complexes of quinoline–imine ligands was developed with peresters as oxidants under mild reaction conditions, which converted benzylic methylenes directly into benzylic alcohols and esters by means of direct C–H bond functionalization. [Copyright &y& Elsevier]

Carboxy marks the spot: A carboxy‐directed asymmetric hydrogenation of 1,1‐diarylethenes and 1,1‐dialkylethenes with chiral iridium/spiro phosphine–oxazoline catalysts has been developed. A wide range of chiral diarylethanes and chiral γ‐methyl fatty acids were synthesized with excellent enantioselectivity (see scheme). [ABSTRACT FROM AUTHOR]

Breit einsetzbar ist die hier beschriebene carboxygesteuerte asymmetrische Hydrierung von 1,1 ‐ Diarylethenen und 1,1 ‐ Dialkylethenen mit chiralen Katalysatoren aus Iridium und einem Spiro ‐ Phosphan ‐ Oxazolin. Sie liefert chirale Diarylethane bzw. γ ‐ Methylfettsäuren mit ausgezeichneter Enantioselektivität. [ABSTRACT FROM AUTHOR]

Abstract: A highly enantioselective rhodium-catalyzed hydrogenation of both (Z)- and (E)-β-arylenamides was developed by using monodentate chiral spiro phosphite and phosphine ligands, respectively. The hydrogenation reaction provides an efficient access to optically active β-arylisopropylamines, important building blocks for the synthesis of biologically active compounds. [Copyright &y& Elsevier]

Carbon–heteroatom bonds (C–X) are ubiquitous and are among the most reactive components of organic compounds. Therefore investigations of the construction of C–X bonds are fundamental and vibrant fields in organic chemistry. Transition-metal-catalyzed heteroatom–hydrogen bond (X–H) insertions via a metal carbene or carbenoid intermediate represent one of the most efficient approaches to form C–X bonds. Because of the availability of substrates, neutral and mild reaction conditions, and high reactivity of these transformations, researchers have widely applied transition-metal-catalyzed X–H insertions in organic synthesis. Researchers have developed a variety of rhodium-catalyzed asymmetric C–H insertion reactions with high to excellent enantioselectivities for a wide range of substrates. However, at the time that we launched our research, very few highly enantioselective X–H insertions had been documented primarily because of a lack of efficient chiral catalysts and indistinct insertion mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: By using iridium catalyst based on chiral spiro phosphine–oxazoline ligands, the hydrogenation of α-arylcinnamic acids was accomplished under ambient pressure and low catalyst loading (as low as 0.01 mol %), providing useful 2,3-diarylpropionic acids in high yields with excellent enantioselectivities (up to 99% ee). A catalytic enantioselective synthesis of (S)-equol with the present hydrogenation reaction as a key step was accomplished starting from commercially available starting materials in six steps with 48.4% overall yield. [Copyright &y& Elsevier]

A copper-catalyzed asymmetric O-H insertion of α-di�azo phosphonates with alcohols by using chiral spiro bisoxazoline ligands was developed. The insertion reaction exhibited good yields (up to 89%) with high enantioselectivities (up to 98% ee) and provided an efficient approach for synthesis of enantiomerically enriched α-alkoxy and hydroxy phosphonate derivatives starting from readily available materials. [ABSTRACT FROM AUTHOR]

Abstract: A palladium-catalyzed asymmetric umpolung allylation reaction of imines with allylic alcohols has been developed. In the presence of chiral spiro phosphoramidite ligand 4, the allylation was accomplished with high yields and good enantioselectivities. The use of highly stable and easily available allylic alcohols instead of allylic metal reagents facilitated the preparation of chiral homoallylic amines. [ABSTRACT FROM AUTHOR]

Abstract: A palladium-catalyzed asymmetric allylation of isatins with allylic alcohols as an allyl donor was developed by using chiral spiro phosphoramidite ligands. A variety of chiral tertiary homoallylic alcohols 3-allyl-3-hydroxy-2-oxindoles were prepared directly from allylic alcohols in one step with excellent yields and moderate enantioselectivities. This represents the first catalytic asymmetric allylation of ketones with allylic alcohol as the allylating agent. [Copyright &y& Elsevier]

Abstract: Two novel chiral spiro nitrogen-containing ligands, 7,7′-bis(2-pyridinecarboxamido)-1,1′-spirobiindane (abbreviated as SIPAD) and 7,7′-bis(2-quinolinecarboxamido)-1,1′-spirobiindane (abbreviated as SIQAD), were conveniently prepared from 1,1′-spirobiindane-7,7′-dicarboxylic acid in high yields (85% and 84%, respectively) in two steps. The cobalt complexes prepared in situ from Co(OAc)2 and the ligands have been proven to be efficient catalysts for the asymmetric Michael addition reaction of malonates to chalcone derivatives. The alkylation products were obtained in high yields with moderate enantiomeric excesses under mild reaction conditions. [Copyright &y& Elsevier]

Abstract: C 2-Symmetric 9,9′-spirobifluorenes with 2,2′-, 3,3′-, and 4,4′-dihydroxyls were conveniently prepared from 1,2-dibromobenzene. The palladium-catalyzed coupling reaction of 1,2-dibromobenzene with methoxyphenylmagnesium bromide or methoxyphenylboronic acid provided methoxy substituted 2-bromobiphenyls. Lithium–bromine exchange with n-butyllithium, followed by reaction with dimethyl carbonate afforded di[2-(methoxyphenyl)phenyl]ketones as the key intermediates. A continuous ring-closure induced by a strong Lewis acid and demethylation gave dihydroxy-9,9′-spirobifluorenes. The racemic dihydroxy products were resolved by inclusion crystallization using chiral resolving reagents or separated by chiral HPLC. [Copyright &y& Elsevier]

Abstract: A new type of bisoxazoline ligand 4 (abbreviated as SpiroBOX) containing a chiral spirobiindane scaffold were easily prepared in high yields from enantiomerically pure 1,1′-spirobiindane-7,7′-diol (SPINOL) with 1,1′-spirobiindane-7,7′-dicarboxylic acid as the key intermediate. Ligands 4 were applied to the Cu-catalyzed asymmetric cyclopropanation of styrenes with menthyl diazoacetate and allylic oxidation of cyclic alkenes with tert-butyl perbenzoates. The copper complexes of ligands 4 showed high activities and moderate to good enantioselectivities. [Copyright &y& Elsevier]

Abstract: Two new organocatalysts derived from l-proline and a novel chiral spiro diamine bearing a C 2 symmetric backbone, were introduced for an asymmetric aldol reaction in moderate to good asymmetric induction in up to 76% ee and high yields. [Copyright &y& Elsevier]

Three chiral 4,4′-substituted 1,1′-spirobiindane-7,7′-diols and related monodentate spiro phosphoramidite ligands have been readily synthesized from enantiomerically pure 1,1′-spirobiindane-7,7′-diol. Excellent enantioselectivities were obtained with these new ligands in the rhodium-catalyzed asymmetric hydrogenation of dehydroamino acid derivatives and enamides. Comparing SIPHOS, ligands 4,4′-dibromo-SIPHOS and 4,4′-diphenyl-SIPHOS gave similarly high enantioselectivities although the rates in hydrogenations of enamides are somewhat slower. Methoxy substituents at the 4,4′-position of ligands slightly reduced enantioselectivities of hydrogenation reactions. [Copyright &y& Elsevier]

The nuanced role of spin effects remains a critical gap in designing proficient open‐shell catalysts. This study elucidates an iron‐catalyzed allylic C(sp3)−H silylation/alkyne hydrosilylation reaction, in which the spin state of the open‐shell iron catalyst dictates the reaction kinetics and pathway. Specifically, spin crossover led to alkyne hydrosilylation, whereas spin conservation resulted in a novel allylic C(sp3)−H silylation reaction. This chemoselectivity, governed by the spin‐crossover efficiency, reveals an unexpected dimension in spin effects and a first in the realm of transition‐metal‐catalyzed in situ silylation of allylic C(sp3)−H bonds, which had been previously inhibited by the heightened reactivity of alkenes in hydrosilylation reactions. Furthermore, this spin crossover can either accelerate or hinder the reaction at different stages within a single catalytic reaction, a phenomenon scarcely documented. Moreover, we identify a substrate‐assisted C−H activation mechanism, a departure from known ligand‐assisted processes, offering a fresh perspective on C−H activation strategies. [ABSTRACT FROM AUTHOR]

The nuanced role of spin effects remains a critical gap in designing proficient open‐shell catalysts. This study elucidates an iron‐catalyzed allylic C(sp3)−H silylation/alkyne hydrosilylation reaction, in which the spin state of the open‐shell iron catalyst dictates the reaction kinetics and pathway. Specifically, spin crossover led to alkyne hydrosilylation, whereas spin conservation resulted in a novel allylic C(sp3)−H silylation reaction. This chemoselectivity, governed by the spin‐crossover efficiency, reveals an unexpected dimension in spin effects and a first in the realm of transition‐metal‐catalyzed in situ silylation of allylic C(sp3)−H bonds, which had been previously inhibited by the heightened reactivity of alkenes in hydrosilylation reactions. Furthermore, this spin crossover can either accelerate or hinder the reaction at different stages within a single catalytic reaction, a phenomenon scarcely documented. Moreover, we identify a substrate‐assisted C−H activation mechanism, a departure from known ligand‐assisted processes, offering a fresh perspective on C−H activation strategies. [ABSTRACT FROM AUTHOR]

An asymmetric carbenoid insertion into S–H bonds catalyzed by copper–chiral spiro bisoxazoline complexes has been developed, in which a series of α-mercaptoesters were produced in high yields with moderate to good enantioselectivities (up to 85% ee); this result represents the best enantioselectivity in the catalytic asymmetric carbenoid S–H bond insertion reaction. [ABSTRACT FROM AUTHOR]

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively, and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development. [ABSTRACT FROM AUTHOR]

Stereoconvergent transformation of E/Z mixtures of olefins to products with a single steric configuration is of great practical importance but hard to achieve. Herein, we report an iron‐catalyzed stereoconvergent 1,4‐hydrosilylation reactions of E/Z mixtures of readily available conjugated dienes for the synthesis of Z‐allylsilanes with high regioselectivity and exclusive stereoselectivity. Mechanistic studies suggest that the reactions most likely proceed through a two‐electron redox mechanism. The stereoselectivity of the reactions is ultimately determined by the crowded reaction cavity of the α‐diimine ligand‐modified iron catalyst, which forces the conjugated diene to coordinate with the iron center in a cis conformation, which in turn results in generation of an anti‐π‐allyl iron intermediate. The mechanism of this stereoconvergent transformation differs from previously reported mechanisms of other related reactions involving radicals or metal‐hydride species. [ABSTRACT FROM AUTHOR]

Stereoconvergent transformation of E/Z mixtures of olefins to products with a single steric configuration is of great practical importance but hard to achieve. Herein, we report an iron‐catalyzed stereoconvergent 1,4‐hydrosilylation reactions of E/Z mixtures of readily available conjugated dienes for the synthesis of Z‐allylsilanes with high regioselectivity and exclusive stereoselectivity. Mechanistic studies suggest that the reactions most likely proceed through a two‐electron redox mechanism. The stereoselectivity of the reactions is ultimately determined by the crowded reaction cavity of the α‐diimine ligand‐modified iron catalyst, which forces the conjugated diene to coordinate with the iron center in a cis conformation, which in turn results in generation of an anti‐π‐allyl iron intermediate. The mechanism of this stereoconvergent transformation differs from previously reported mechanisms of other related reactions involving radicals or metal‐hydride species. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The alkenylzincation of internal alkynes is an effective method for the synthesis of multi‐substituted conjugated dienes; however, the current catalytic systems for this reaction are limited in terms of substrate scope and selectivity control, which restricts its practical applications. Herein, we report the first iron‐catalyzed alkenylzincation of internal alkynes, which features mild conditions, simple operation, broad substrate scope (including aryl/alkyl, diaryl, and dialkyl acetylenes), excellent functional group tolerance (tolerating highly active functional groups such as ester, methylthio, amide, sulfonyl, cyano, etc.), and high activity (with a turnover number of up to 11500, the highest record for carbometallation reactions). Notably, the catalytic system described in this article also realized the highly selective vinylzincation of unfunctionalized internal alkynes as well as the alkenylzincation of unsymmetrical diarylacetylenes and dialkyl acetylenes, which have not been achieved with other catalytic systems reported in the literatures. The current study provides a highly selective access to synthetically important multi‐substituted conjugated dienes. [ABSTRACT FROM AUTHOR]

Recently, the application of computational tools to the rational design of catalysts has received considerable attention, but progress has been limited by the reliance on databases and because mechanistic data have been almost neglected. Herein, we report a new strategy for catalyst design, designated catalyst‐oriented design based on elementary reactions (CODER), which fully utilizes mechanistic data, combines the strengths of computational tools and researcher experience. CODER enabled the development of extremely efficient Pd catalysts for C−N coupling, which markedly improved the efficiency of the synthesis of widely used triarylamine optoelectronic materials by enhancing the turnover numbers (up to 340000) to 1–3 orders of magnitude towards literature values. [ABSTRACT FROM AUTHOR]

Recently, the application of computational tools to the rational design of catalysts has received considerable attention, but progress has been limited by the reliance on databases and because mechanistic data have been almost neglected. Herein, we report a new strategy for catalyst design, designated catalyst‐oriented design based on elementary reactions (CODER), which fully utilizes mechanistic data, combines the strengths of computational tools and researcher experience. CODER enabled the development of extremely efficient Pd catalysts for C−N coupling, which markedly improved the efficiency of the synthesis of widely used triarylamine optoelectronic materials by enhancing the turnover numbers (up to 340000) to 1–3 orders of magnitude towards literature values. [ABSTRACT FROM AUTHOR]

An abstract of the article "Enantioselective Iron-Catalyzed Intramolecular Cyclopropanation Reactions" by J.-J. Shen and colleagues is presented.

This is the first asymmetric N-H insertion of α-diazoketones giving α-aminoketones in good yields and with high enantioselectivities. [ABSTRACT FROM AUTHOR]

The carboxy-directed hydrogenation prohibits the isomerization of the terminal olefins, and realizes the chemoselective hydrogenation of various dienes. [ABSTRACT FROM AUTHOR]

The article highlights the chemical equations involved in the enantioselective palladium-catalyzed insertion of aryl-diazoacetates into the O-H bonds of phenols.

Chemical formulas showing highly enantioselective S-H bond insertion cooperatively catalyzed by dirhodium complexes and chiral spiro phosphoric acids are presented.

The transition-metal-catalyzed reaction of diazo compounds with arenes or heteroarenes is an efficient and straightforward approach to functionalize aromatic compounds. This digest summarizes recent progresses on transition-metal-catalyzed asymmetric reactions of diazo compounds with electron-rich (hetero-) arenes, including C–H functionalization, cascade reaction, cyclopropanation, cycloaddition, Buchner reaction and intramolecular dearomatization. [ABSTRACT FROM AUTHOR]

The title methodology allows the preparation of chiral α-substituted carboxylic acids in excellent yields and enantioselectivities. [ABSTRACT FROM AUTHOR]

The synthetic value of this protocol is demonstrated by an efficient preparation of nipecotic acid (VI). [ABSTRACT FROM AUTHOR]

Unsymmetrical peroxides (II) are tested under optimized conditions. [ABSTRACT FROM AUTHOR]