Inorganic ionic polymerization:From biomineralization to materials manufacturing

Biomineralization process regulates the growth of inorganic minerals by complex molecules,proteins,and cells,endowing bio-materials with marvels structures and excellent properties.The intricate structures and compositions found in biominerals have inspired scientists to design and synthesize numerous artificial biomimetic materials.The methodology for controlling the formation of inorganics plays a pivotal role in achieving biomimetic structures and compositions.However,the current approach predominantly relies on the classical nucleation theory,which hinders the precise preparation of inorganic materials by replicating the biomineralization strategy.Recently,the development of“inorganic ionic polymerization”strategy has enabled us to regulate the arrangement of inorganic ions from solution to solid phase,which establishes an artificial way to produce inorganic materials analogous to the biomineralization process.Based on inorganic ionic polymerization,a series of achievements have been realized for the biomimetic preparation,including moldable construction of inorganic materials,hard tissue regeneration,and high-performance biomimetic materials.Moreover,the utilization of inorganic ionic polymerization has also facilitated the production of numerous advanced materials,including novel structures that exceed the current knowledge of materials science.The inorganic ionic polymerization system provides new artificial strategies and methodologies for the controllable synthesis of inorganics,which mimics the biomineralization process,paving the way for the future development of more high-performance materials.

A New Synthetic Approach to Elvucitabine

A new synthetic approach to elvucitabine started from L-xylose via the reactions of 10 steps in an overall yield of 20% was developed. The key steps included trimethylsilyl trifluoromethanesulfonate（TMSOT0-mediated stereocontrolled β-glycosidation and exquisite choice of chloroacetyl group for the protection of hydroxyl groups as well as the corresponding deprotection under notably mild conditions. The structure of elvucitabine, in particular, the stereochemistry thereof, was unambiguously determined by comparison of the physical properties, such as 1H NMR data and the specific rotation, of the synthesized sample with those reported.

Catalytic Arylalkylation of Alkenyl Amines at Remote Sites via Directed Nickel Catalysis

Directing group-assisted, transition metal-catalyzed three-component difunctionalization of alkenes has emerged as a powerful tool to drive molecular complexity. However, this strategy generally works with the substrates bearing directing groups in close proximity to the alkene moieties, due to the preference for formation of kinetically stable five-membered metallacycles. Herein, we have disclosed a complementary strategy to accomplish a nickel-catalyzed remote arylalkylation of alkenyl amines with excellent regioselectivity and diastereofidelity, involving rare six- or seven-membered metallacycles. This general protocol is compatible with a series of δ- and ε-alkenyl amines, providing corresponding valuable δ,ε- and ε,ζ-difunctionalized aliphatic amines that would be difficult to synthesize. The coordination of the bidentate picolinamide auxiliary and the facile oxidative addition of alkyl halides to Ni(I) species are the key to the success of the developed remote olefin dicarbofunctionalization.

Sulfur-promoted,one-pot,and metal-free conversion of aromatic aldehydes to nitriles using an inorganic ammonium salt as the nitrogen source

A simple protocol for the sulfur-promoted conversion of aromatic aldehydes to aromatic nitriles has been developed.This strategy enables the one-pot conversion of inexpensive and readily available aromatic aldehydes into highly valuable aromatic nitriles using a cheap inorganic ammonium salt as the nitrogen source in the absence of metals.Significantly,a broad scope of substrates was explored using this strategy,and various groups,including alkyl,alkoxyl,alkylthiol,hydroxyl,amino,aryl,alkenyl,cyano,carboxyl,and borate ester groups were tolerated,and good to excellent yields were achieved in most cases.Additionally,polycyclic aromatic aldehydes and heteroaromatic aldehydes also could be converted to the corre-sponding nitriles with satisfactory yields.This method can be utilized as a powerful tool for the cyanation of complex molecules.

Contemporary synthesis of bioactive cyclobutane natural products

Many cyclobutane natural products have intriguing biological properties that arise from their fascinating chemical structures.Cyclobutane natural products feature a cyclobutane scaffold as the core or as a part of the spirocyclic or fused cyclic core.However,the highly functionalized nature and the inherent stereochemistry of these cyclobutane natural products,which are associated with their biological activities,pose tremendous challenges to their preparation.In this perspective,we present contemporary advancements in synthetic methods and/or strategies en route to the bioactive cyclobutane natural products.We begin by describing the representative bioactive cyclobutane natural products and then focus on illustrative examples of their syntheses reported from 2018 to 2021.These advances will enable efficient syntheses of cyclobutanes of structural and biological importance.

Synthesis and Acid-Catalyzed Cyclization of 2-Alkenylstilbenes： a New Approach to the Substituted Indenes

A base-catalyzed ring-opening of 1-benzylisochromans 1 firstly produced 2-alkenylstilbenes 2, which then underwent a mild acid-catalyzed intramolecular cyclization to furnish 1,2-disubstituted indenes 3 in high yields. Subsequently, a base-catalyzed isomerization of the 1,2-disubstituted indenes 3 afforded the more stable 2,3-disubstituted indenes 4 in almost quantitative yields.

Synthesis of benzisothiazoles by a three-component reaction using elemental sulfur and ammonium as heteroatom components under transition metal-free conditions

A strategy for the synthesis of benzisothiazoles by a three-component reaction was developed using elemental sulfur and ammonium as heteroatom components under transition metal-free conditions.The reaction is preferably based on pyridine or quinoline ring substrate,and good to excellent yields can be obtained.Notably,this reaction has been applied to the gram-scale synthesis of bioactive molecules.