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Comprehensive Summary: The 21st century has witnessed a continuous evolution in the development of boron‐stereogenic chemistry. Since the 1990s, various innovations for the synthesis of tetracoordinate boron‐stereogenic compounds, which exhibited great potential applications, have been demonstrated by synthetic chemists. This paper reviews the significant progress and recent advances towards the assembly of enantioenriched boron‐stereogenic compounds, and hopes to shed light on new perspectives and inspire further research in this emerging field. [ABSTRACT FROM AUTHOR]

We have developed an efficient modular asymmetric synthesis of azahelicenes through an organocatalyzed asymmetric multicomponent reaction from readily available polycyclic aromatic amines, aldehydes, and (di)enamides, by employing a central‐to‐helical chirality conversion strategy. A series of aza[5]‐ and aza[4]helicenes bearing various substituents were readily afforded through this one‐pot sequential enantioselective Povarov reaction/oxidative aromatization process, with good yields and high enantioselectivities. The fruitful and diverse derivatizations of the chiral azahelicene products demonstrated the potential of this method, and a preliminary application of the azahelicene derivative as a chiral organocatalyst was showcased. The photophysical and chiroptical properties of these azahelicenes, particularly the acid/base‐triggered switching of these properties, were also well studied, which may find potential applications in the development of novel organic optoelectronic materials. [ABSTRACT FROM AUTHOR]

The differentiation of enantiomers is of significance in synthetic chemistry and pharmaceutical chemistry. Herein, we report a facile method for chirality sensing of monoalcohols, a challenging target due to the poor reactivity, by combining dynamic covalent chemistry with helical chirality. Four diphenylethene (DPE) derived cyclic hemiaminals were constructed, and the incorporation of a broad range of alcohols and thiols with high efficiency was achieved. The reversibility was further verified by dynamic component exchange. The helical chirality of the DPE motif was induced through chirality transfer by the central chirality of the analytes, resulting in circular dichroism responses. The chirality differentiation of seven chiral secondary alcohols including both alkyl and aryl alcohols was realized, further allowing the quantification of enantiomeric excess with high accuracy. The results described should lay a foundation for future endeavors in chemical sensing, asymmetric synthesis, and chiroptical materials. [ABSTRACT FROM AUTHOR]

1,3,2‐diazaphospholene hydrides (DAP−H) enable smooth conjugate reduction of polarized double bonds. The transiently formed phosphorus‐enolate provides a potential platform for reductive α‐functionalizations. In this respect, asymmetric C‐heteroatom bond forming processes are synthetically appealing but remain elusive. We report a 1,3,2‐diazaphospholene‐catalyzed three‐step cascade reaction of N‐sulfinyl acrylamides comprised of conjugate reduction, [2,3]‐sigmatropic aza‐Mislow‐Evans rearrangement and subsequent S−O bond cleavage. The obtained enantio‐enriched α‐hydroxy amides are formed in good yields and excellent enantiospecificity. The stereo‐defined P‐bound N,O‐ketene aminal ensures an excellent transfer of chirality from the sulfur stereocenter to α‐carbon. The transformation operates under mild conditions at ambient temperature. Moreover, DAP−H is a competent reductant for the cleavage of formed sulfenate ester, eliminating the extra step in traditional Mislow‐Evans processes. [ABSTRACT FROM AUTHOR]

Dynamically controlling the supramolecular chirality is of great significance in development of functional chiral materials, which is thus essential for the specific function implementation. As an external energy input, light is remote and accurate for modulating chiral assemblies. In non‐polarized light control, some photochemically reactive units (e. g. azobenzene, ɑ‐cyanostilbene, spiropyran, anthracene) or photo‐induced directionally rotating molecular motors were designed to drive chiral transfer or amplification. Besides, photoexcitation induced assembly based physical approach was also explored recently to regulate supramolecular chirality beyond photochemical reactions. In addition, circularly polarized light was applied to induce asymmetric arrangement of organic molecules and asymmetric photochemical synthesis of inorganic metallic nanostructures, in which both wavelength and handedness of circularly polarized light have effects on the induced supramolecular chirality. Although light‐triggered chiral assemblies have been widely applied in photoelectric materials, biomedical fields, soft actuator, chiral catalysis and chiral sensing, there is a lack of systematic review on this topic. In this review, we summarized the recent studies and perspectives in the constructions and applications of light‐responsive chiral assembled systems, aiming to provide better knowledge for the development of multifunctional chiral nanomaterials. [ABSTRACT FROM AUTHOR]

Without chiral induction the emergence of homochirality from achiral molecules is rather serendipitous, as the rationale is somewhat ambiguous. We herein provide a plausible solution. From achiral precursors are formed a pair of interconverting cage conformers that exhibit a C3‐axis as the only symmetry element. When their interconversion is impeded with intramolecular H‐bonding, each conformer self‐sorts into a homochiral crystal, which is driven by a helical network of multivalent intermolecular interactions during the self‐assembly of homochiral cage conformers. As no chiral induction is involved throughout, we believe our study could enlighten the rational design for the emergence of homochirality with several criteria: 1) formation of a molecule without inversion center or mirror plane; 2) suppression of the enantiomeric interconversion, and introduction of multivalent interactions along the helical trajectory of screw symmetry within the resulting superstructure. [ABSTRACT FROM AUTHOR]

Though [60]fullerene is an achiral molecular nanocarbon with Ih symmetry, it could attain an inherent chirality depending upon a functionalization pattern. The conventional chiral induction of C60 relies mainly upon a multiple addition affording a mixture of achiral and chiral isomers while their chiral function would be largely offset by the existence of pseudo‐mirror plane(s). These are major obstacles to proceed further study on fullerene chirality and yet leave its understanding elusive. Herein, we showcase a carbene‐mediated synthesis of C1‐symmetric chiral open [60]fullerenes showing an intense far‐red to near‐infrared absorption. The large dissymmetry factor of |gabs|=0.12 was achieved at λ=820 nm for circular dichroism in benzonitrile. This is, in general, unachievable by other small chiral organic molecules, demonstrating the potential usage of open [60]fullerenes as novel types of chiral chromophores. [ABSTRACT FROM AUTHOR]

The chirality of molecules is a concept that explains the interactions in nature. We may observe the same formula but different organizations revolving around the chiral center. Since Pasteur's meticulous observation of sodium ammonium tartrate crystals' structure, scientists have discovered many features of chiral molecules. The number of newly approved single enantiomeric drugs increases every year and takes place in the market. Thus, separation or resolution methods of racemic mixtures are of continued importance in the efficacy of drugs, installation of affordable production processes, and convenient synthetic chemistry practice. This article presents the asymmetric synthesis approaches and the classification of direct resolution methods of chiral molecules. [ABSTRACT FROM AUTHOR]

The para‐Claisen rearrangement of aryl 1‐propargyl ethers involves two‐step [3,3]‐sigmatropic rearrangements and dearomatization process, which has high activation barriers and is of challenge. Here we discovered thermal para‐Claisen rearrangement of naphthyl 1‐propargyl ethers, and it enabled the formation of formal para‐C−H propargylation products upon rearomatization. Chirality transfer occurred if optically active propargyl ethers were employed, leading to the construction of aryl/propargyl‐containing stereogenic centers. Moreover, catalytic asymmetric dearomatization of naphthyl 1‐propargyl ethers with different substitution at para‐position gave access to benzocyclohexenones bearing all‐carbon quaternary stereocenters. The reaction was accelerated by a chiral N,N′‐dioxide/Co(OTf)2 complex catalyst to achieve high yields (up to 98 %) and high enantioselectivities (up to 93 % ee). The DFT calculations and experimental results provided important clues to clarify the para‐Claisen rearrangement process as well as the chiral induction and remote delivery. [ABSTRACT FROM AUTHOR]

In helical polymers, helical sense induction is usually commanded by teleinduction mechanism, where the largest substituent of the chiral residue directly attached to the main chain is the one that commands the helical sense. In this work, different helical structures with different helical senses are induced in a helical polymer [poly‐(phenylacetylene)] when the conformational composition of two different dihedral angles of a pendant group with more than two chiral residues is tamed. Thus, while the dihedral angle at chiral residue 1 [(R)‐ or (S)‐alanine], attached to the backbone, produces an extended or bent conformation in the pendant resulting in two scaffolds with different stretching degree, the second dihedral angle at chiral residue 2 [(R)‐ or (S)‐methoxyphenylacetamide] places the substituents of this chiral center in a different spatial orientation, originating opposite helical senses at the polymer that are induced through a total control of the "chiral overpass effect". [ABSTRACT FROM AUTHOR]

The application of Suzuki–Miyaura coupling reaction to forge the atropisomeric biaryls has seen remarkable progress but exploration of this chemistry to directly forge chiral C(aryl)‐C(alkene) axis is underdeveloped. The replacement of arene substrates by alkenes intensifies the challenges in terms of reactivity, configurational atropostability of product and selectivity control. By meticulous ligand design and fine‐tuning of reaction parameters, we identified a highly active 3,3′‐triphenylsilyl‐substituted phosphite ligand to realize arene‐alkene Suzuki–Miyaura coupling of hindered aryl halides and vinyl boronates under very mild conditions. The axially chiral acyclic aryl‐alkenes were generated in commendable efficiency, enantioselectivity and E/Z selectivity. [ABSTRACT FROM AUTHOR]

Ladderane phospholipids, with their unusual ladder‐like arrangement of concatenated cyclobutane rings, represent an architecturally unique class of natural products. However, despite their fascinating structure and other necessary impetus, only a few synthetic studies of these molecules have been reported so far. We have now devised a concise total synthesis of [3]‐ladderanol, a component of natural ladderane phospholipids, using an organocatalytic enantioselective desymmetrizing formal C(sp2)−H alkylation. Our synthetic strategy rests on the late‐stage introduction of chirality, thus allowing facile access to both enantiomers of [3]‐ladderanol as well as an analogue. This is the first time a desymmetrization strategy is applied to the synthesis of [3]‐ladderanol. The scope of this desymmetrizing C(sp2)−H alkylation of meso‐cyclobutane‐fused cyclohexenediones is also presented. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric synthesis of chiral endocyclic allenes remains a challenge in allene chemistry owing to unfavored tension and complex chirality. Here, we present a new relay strategy merging Pd‐catalyzed asymmetric [3+2] annulation with enyne‐Cope rearrangement, providing a facile route to chiral 9‐membered endocyclic allenes with high efficiency and enantioselectivity. Moreover, theoretical calculations and experimental studies were performed to illustrate the critical, but unusual Cope rearrangement that allows for the complete central‐to‐axial chirality transfer. [ABSTRACT FROM AUTHOR]

Circularly polarized light (CPL) is key to asymmetric photochemistry as it could impart the chiral organization information into chemical products. Here, we demonstrate the circular polarization capacity of chiral cellulose nanocrystal (CNC) films to trigger photo‐alignment of achiral supramolecular polymers into helical structures. Right‐handed transmitted (T‐) CPL was generated from self‐assembled CNC films, which induced amorphous azobenzene (Azo) supramolecular polymers into chiral structures. The chiral induction effect of T‐CPL is enhanced on Azo polymers with longer spacers. The absorptive dissymmetry factor (gabs) values of liquid‐crystal supramolecular polymers can be amplified significantly (over 10 times) after T‐CPL irradiation. Moreover, by integrating carbon dots into CNC films, CPL emission with a considerable luminescence dissymmetry factor (glum) up to −0.66 was achieved, and it could be used for the photo‐alignment of Azo polymers with high chiroptical properties. This work provides new insight for the photo modulation of supramolecular polymers by CPL‐active materials. [ABSTRACT FROM AUTHOR]

Enantioenriched, highly functionalized cyclopropane derivatives were prepared by a simple and green approach using monosaccharide‐based chiral crown ethers as phase transfer catalysts. The Michael‐initiated ring closure (MIRC) reactions of diethyl bromomalonate with 2‐cyano‐3‐phenylacrylate took place with complete diastereoselectivity in the presence of chiral lariat ethers derived from carbohydrates and enantioselectivity up to 87 % ee was achieved. Among the catalysts tested, the monoaza‐15‐crown‐5 lariat ether having a methyl β‐d‐glucopyranoside unit and a 2‐(3,4‐dimethoxyphenyl)ethyl group on the nitrogen generated the highest asymmetric induction (87 % ee). In the reactions of analogous 2‐cyano‐3‐arylacrylates, enantioselectivity was in the range of 8–91 % ee. [ABSTRACT FROM AUTHOR]

Chirality represents a fundamental structure in nature and the induction and reversible modulation of supramolecular chirality with feasible techniques is of great value in the design of new chiroptical smart materials. Herein, two kinds of azobenzene side‐chain polymers (without spacer: Azo‐PMA0; with 6 spacers: Azo‐PMA6) are synthesized, the length of spacer and azobenzene chromophores play a vital role in chirality transfer and modulation. The supramolecular chiral arrangement of Azo‐PMA0 (amorphous phase) can be completely controlled and reversibly modulated over multiple cycles by 450 nm circularly polarized light driven by the supramolecular interaction between azo groups of polymer chains, with an absorption dissymmetry factor (g) value of 0.0019. The chiroptical properties of Azo‐PMA6 (liquid crystal state) can also be reversibly modulated by UV light and thermal annealing treatment during trans‐cis isomerization of azo chromophore, with the g‐value changes from 0–0.038. The successful construction of reversible chiral induction and modulation based on side chain azobenzene polymers may pave the way for designing photo‐switchable functional materials. [ABSTRACT FROM AUTHOR]

A rhodium(II)‐catalyzed asymmetric cyclooligomerization of bifunctional monomers possessing triazolyl and vinyl groups at 2,3‐ and 3,4‐positions on the thiophene ring is studied. Structurally interesting cyclic dimers in which thienylene and cyclopropylene units are alternately connected are obtained as the major components. The eight‐membered rings in the center are non‐planar and adopt a tub‐shaped conformation. We also observe the phenomenon of racemization caused by a tub‐to‐tub ring‐flipping, the activation energy of which is determined as 108 kJ mol−1 by electronic circular dichroism spectra measurement. [ABSTRACT FROM AUTHOR]

Transformations of enantioenriched donor‐acceptor (D−A) cyclopropylcarbinols to enantioenriched 1‐arylnaphthalenes that bear an ortho‐substituent on a benzene ring provided a successful chirality‐exchange method with a high level of stereoinduction. A central chirality‐transfer step, i. e. a Lewis‐acid‐mediated ring‐opening cyclization of enantioenriched D‐A cyclopropylcarbinols (97 to >99 % ee), afforded 1‐aryl‐1,2‐dihydronaphthalenes with an ortho‐substituent (Me, Br, OMe, OBn, or OiPr) on the benzene ring with high enantioselectivity (97 to >99 % ee). The central‐to‐axial chirality‐exchange step, i. e. the dehydrogenation of the obtained enantioenriched 1‐aryl‐1,2‐dihydronaphthalenes using DDQ, furnished the axially chiral 1‐arylnaphthalenes with high enantioselectivity (90 to >99 % ee). Importantly, we developed a highly enantioselective synthesis of a 1‐arylnaphthalene with an ortho‐alkoxy group on the benzene ring. Moreover, we improved the chirality exchange to furnish a 1‐arylnaphthalene with an ortho‐alkoxy‐substituted benzene ring in high yield with high ee. [ABSTRACT FROM AUTHOR]

We report a diastereoselective Mannich‐type reaction of 3‐alkyloxindole with N‐tert‐butanesulfinyl imino ester. This method provides a concise route to α‐amino acid derivatives bearing a 3‐alkyloxindole structural motif. This protocol has the advantage of using readily accessible starting materials and is operationally simple. A plausible transition‐state mode for the observed stereoselectivity is presented. [ABSTRACT FROM AUTHOR]

We report the asymmetric synthesis of homochiral metal–organic materials (MOMs) in chiral gels from achiral components. The enantioselectivity of MOMs depends on the chirality of the gel, whereas the synthesis performed in solution phase and achiral gels resulted in conglomerates. [ABSTRACT FROM AUTHOR]

Intramolecular Sn2′ cyclization of α‐amino ester enolates provided piperidine derivatives with vicinal quaternary‐tertiary stereocenters with excellent diastereo‐ and enantioselectivity via memory of chirality and the Thorpe‐Ingold effect. DFT calculations provided a mechanistic rationale for the increase in chirality preservation via the Thorpe‐Ingold effect. This new method has the potential to be integrated into concise asymmetric synthesis of bioactive molecules containing multisubstituted piperidine moieties. [ABSTRACT FROM AUTHOR]

Chirality is ubiquitous in nature with primary cellular functions that include construction of right‐/left‐handed helix and selective communications among diverse biomolecules. Of particularly intriguing are the chiral peptide‐based materials that can be deliberately designed to change physicochemistry properties via tuning peptide sequences. Critically, understanding their chiral effects are fundamental for the development of novel materials in chemistry and biomedicine fields. Here, we review recent researches on chirality in peptide‐based materials, summarizing relevant typical chiral effects towards recognition, amplification, and induction. Driven forces for the chiral discrimination in affinity interaction as well as the handedness preferences in supramolecular structure formation at both the macroscale and microscale are illustrated. The implementation of such chirality effects of artificial copolymers, assembled aggregates and their composites in the fields of bioseparation and bioenrichment, cell incubation, protein aggregation inhibitors, chiral smart gels, and bionic electro devices are also presented. At last, the challenges in these areas and possible directions are pointed out. The diversity of chiral roles in the origin of life and chirality design in different organic or composite systems as well as their applications in drug development and chirality detection in environmental protection are discussed. [ABSTRACT FROM AUTHOR]