<i>tert</i>-Butyl Sulfoxide as a Starting Point for the Synthesis of Sulfinyl Containing Compounds

Sulfoxides bearing a <i>tert</i>-butyl group can be activated using <i>N</i>-bromosuccinimide (NBS) under acidic conditions and then subsequently treated with a variety of nitrogen, carbon, or oxygen nucleophiles to afford a wide range of the corresponding sulfinic acid amides, new sulfoxides, and sulfinic acid esters

Mild and Catalyst-Free Petasis/Decarboxylative Domino Reaction: Chemoselective Synthesis of <i>N</i>‑Benzyl Propargylamines

Multicomponent domino reactions are attractive for assembling functionalized compounds. To this end, a one-pot catalyst-free chemoselective synthesis of <i>N</i>-benzyl propargylamines is reported with good functional group compatibility. This mild process involves <i>in situ</i> formation of an active amine through Petasis reaction of primary amines, formaldehyde solution, and boronic acids, which reacts with propiolic acids to give product in up to 94% yield via decarboxylative coupling reaction

Asymmetric Reduction of <i>tert</i>-Butanesulfinyl Ketimines by N‑Heterocyclic Carbene Boranes

N-heterocyclic carbene borane (NHC-borane) based on a triazole core is demonstrated for the first time to be efficient for reduction of a variety of <i>tert</i>-butanesulfinyl ketimines. Up to 95% yield and up to >99% diastereomeric excess were achieved. NHC-borane exhibited excellent activities that are more efficient than or comparable to commonly used reductive reagents such as NaBH₄, NaBH₃CN, l-selectride, Ru catalyst, or BH₃–THF

Thermolysis-Induced Two- or Multicomponent Tandem Reactions Involving Isocyanides and Sulfenic-Acid-Generating Sulfoxides: Access to Diverse Sulfur-Containing Functional Scaffolds

Direct reaction of isocyanides with some sulfenic-acid-generating sulfoxides led to the effective formation of the corresponding thiocarbamic acid <i>S</i>-esters in good to high yields. A multicomponent reaction involving isocyanide, sulfoxide, and a suitable nucleophile has also been developed, providing ready access to a diverse range of sulfur-containing compounds, including isothioureas, carbonimidothioic acid esters, and carboximidothioic acid esters

Synthesis of 3‑Substituted Aryl[4,5]isothiazoles through an All-Heteroatom Wittig-Equivalent Process

Extending the previous use of <i>tert</i>-butyl sulfoxide as the sulfinyl source, intramolecular sulfinylation of sulfonamides was successfully performed. The resulting sulfinimides were not isolated and instead were believed to go through an all-heteroatom Wittig-equivalent process to eventually afford aryl­[4,5]­isothiazoles in high yields

Unusual Long-Range Ordering Incommensurate Structural Modulations in an Organic Molecular Ferroelectric

The incommensurate (IC) behaviors of ferroelectrics have been widely investigated in inorganic oxides as an exciting branch for aperiodic materials, whereas it still remains a great challenge to achieve such intriguing effects in organic systems. Here, we present that successive ordering of dynamic dipoles in an organic molecular ferroelectric, <i>N-</i>isopropylbenzylaminium trichloroacetate (<b>1</b>), enables unusual incommensurately modulated structures between its paraelectric phase and ferroelectric phase. In particular, <b>1</b> exhibits three distinct IC states coupling with a long-range ordering modulation. That is, the incommensurately modulated lattice is ∼7 times as large as its periodic prototype, and the IC structure is well solved using a (3 + 1)<i>D</i> superspace group with the modulated wavevector <b><i>q</i></b> = (0, 0, 0.1589). To the best of our knowledge, <b>1</b> is the first organic ferroelectric showing such a long-range ordering IC structural modulation. In addition, structural analyses reveal that slowing down dynamic motions of anionic moieties accounts for its modulation behaviors, which also results in dramatic reorientation of dipolar moments and concrete ferroelectric polarization of <b>1</b> (∼0.65 μC/cm²). The combination of unique IC structural modulations and ferroelectricity makes <b>1</b> a potential candidate for the assembly of an artificially modulated lattice, which will allow for a deep understanding of the underlying chemistry and physics of aperiodic materials

Plastic Transition to Switch Nonlinear Optical Properties Showing the Record High Contrast in a Single-Component Molecular Crystal

To switch bulk nonlinear optical (NLO) effects represents an exciting new branch of NLO material science, whereas it remains a great challenge to achieve high contrast for “on/off” of quadratic NLO effects in crystalline materials. Here, we report the supereminent NLO-switching behaviors of a single-component plastic crystal, 2-(hydroxymethyl)-2-nitro-1,3-propanediol (<b>1</b>), which shows a record high contrast of at least ∼150, exceeding all the known crystalline switches. Such a breakthrough is clearly elucidated from the slowing down of highly isotropic molecular motions during plastic-to-rigid transition. The deep understanding of its intrinsic plasticity and superior NLO property allows the construction of a feasible switching mechanism. As a unique class of substances with short-range disorder embedded in long-range ordered crystalline lattice, plastic crystals enable response to external stimuli and fulfill specific photoelectric functions, which open a newly conceptual avenue for the designing of new functional materials

One-pot synthesis of α,α-disubstituted Aryl-1-ethanones <i>via</i> the Wittig-Horner reaction

<p></p> <p>A one-pot methodology for the synthesis of α,α-disubstituted aryl-1-ethanones <i>via</i> the Wittig-Horner reaction has been developed and described in this manuscript. Both aryl/alkyl and dialkyl α-branched arylethanone were obtained in high yields (up to 96%) without the use of any metal catalysts. A total of 14 α,α-disubstituted arylethanone derivatives were synthesized based on this simple method that easily converts the carbonyl carbon (sp²) into the sp³ carbon. This versatile method is expected to further promote the use of substituted ketones as synthetic building blocks to construct a variety of α-branched aryl ketones.</p

Construction of Interpenetrated Ruthenium Metal–Organic Frameworks as Stable Photocatalysts for CO₂ Reduction

Poor stability has long been a major obstacle to the practical applications of metal–organic framework (MOF) photocatalysts. This problem can be overcome by the use of structural interpenetration. In this work, by modifying Ru metalloligands, we have rationally designed two Ru–polypyridine based MOFs (with non-interpenetrated and interpenetrated structures, respectively), both of which exhibit similar photocatalytic activities for CO₂ photoreduction. Remarkably, the interpenetrated Ru-MOF possesses good photocatalytic durability and recyclability, and shows much higher thermal and photic stability in comparison with its non-interpenetrated counterpart. To the best of our knowledge, this is the first time that the stability of MOF photocatalysts was improved by using structural interpenetration

Microwave-Assisted or Cu–NHC-Catalyzed Cycloaddition of Azido-Disubstituted Alkynes: Bifurcation of Reaction Pathways

Microwave irradiation promoted the intramolecular cycloaddition of 2-azidoacetamides derived from α-chiral propargylic amines, affording 1,4,5-trisubstituted triazoles <b>4</b> bearing a chiral aminomethyl side chain at C5. In contrast, for the same substrates <b>3a</b>–<b>k</b>, Cu­(I)–NHC complexes catalyzed the intermolecular cycloaddition in an unexpected desilylative fashion, leading to 1,4-disubstituted triazoles <b>5</b>. This demonstrates that 1-silyl alkynes can be employed as substrates for CuAAC with a suitable coupling partner