Directional hearing: from biophysical binaural cues to directional hearing outdoors

We report the cyclization of 3-substituted <i>N</i>-acetylindoles for the straightforward synthesis of 3,3-spiroindolines via the Friedel–Crafts reaction of an appended aryl group or the formal [2 + 2] cycloaddition of an appended alkene. Our strategy involves an Umpolung of the C2C3 bond of the indole nucleus during FeCl₃-mediated hydroarylation or annulation reactions

Synthesis of 3‑Substituted 3‑Bromo-1-phenylallenes from Alkynylcycloheptatrienes

A new method has been developed for the preparation of 3-bromo-1-phenylallenes from 7-alkynylcycloheptatrienes and <i>N</i>-bromosuccinimide. Trisubstituted bromoallenes were obtained at room temperature in moderate to excellent yields. Functionalization of the carbon–bromine bond via Pd- or Cu-catalyzed cross-coupling reactions easily provided substituted allenes

Synthesis of 3‑Substituted 3‑Bromo-1-phenylallenes from Alkynylcycloheptatrienes

A new method has been developed for the preparation of 3-bromo-1-phenylallenes from 7-alkynylcycloheptatrienes and <i>N</i>-bromosuccinimide. Trisubstituted bromoallenes were obtained at room temperature in moderate to excellent yields. Functionalization of the carbon–bromine bond via Pd- or Cu-catalyzed cross-coupling reactions easily provided substituted allenes

Aluminum-Catalyzed Intramolecular Vinylation of Arenes by Vinyl Cations

This study addresses the challenges associated with vinyl cation generation, a process that traditionally requires quite specific counterions. Described herein is a novel intramolecular vinylation of arenes catalyzed by aluminum(III) chloride, utilizing practical conditions and readily available vinyl triflates derived from 2-aceto-3-arylpropionates. Comprehensive experimental data support diverse carbocycle synthesis, exemplified by indenes and higher analogues. Control experiments verify the applicability of the vinylation protocol, and synthetic applications showcase a potent tubulin polymerization inhibitor with anticancer properties. Density functional theory computations reveal a Lewis-acid-driven mechanism involving triflate moiety abstraction to generate a reactive vinyl cation

Molecular versus Ionic Structures in Adducts of GaX₃ with Monodentate Carbon-Based Ligands

A molecular donor–acceptor adduct has been isolated by the reaction of the <i>N</i>-heterocyclic carbene 1,3-dimethyl imidazol-2-ylidene (diMe-IMD) with GaCl₃. In contrast, the structurally related, yet much more nucleophilic, 1,3-dimethyl-2-methylene-2,3-dihydro-1<i>H</i>-imidazole (diMe-MDI) gave rise to ion pairs of type [L₂GaX₂]­[GaX₄], where X = Cl, Br, or I. With IBioxMe₄, a <i>N</i>-heterocyclic carbene that is more nucleophilic than diMe-IMD, the outcome of the reaction was dependent on the nature of the halide. Ionic 1:1 adducts between monodentate ligands and GaX₃ salts have only one precedent in the literature. The peculiar behavior of carbon-based ligands was explained on the basis of their electronic properties and reaction kinetics

Radical-Mediated Dearomatization of Indoles with Sulfinate Reagents for the Synthesis of Fluorinated Spirocyclic Indolines

The dearomative introduction of trifluoromethyl and 1,1-difluoroethyl radicals, generated from their corresponding sulfinate salts, into the C2 position of indole derivatives allows the diastereoselective synthesis of three-dimensional 3,3-spirocyclic indolines over C–H functionalized indoles

Dearomative Diallylation of <i>N</i>‑Acylindoles Mediated by FeCl₃

Three-dimensional indolines possessing two contiguous-stereogenic centers were obtained stereoselectively via the FeCl₃-mediated dearomative introduction of two allyl groups to <i>N</i>-acylindoles with allyltrimethylsilane. Synthetic transformations allowed obtention of <i>trans</i>-tetrahydrocarbazoles and an aza[4.4.3]­propellane scaffold by RCM. Selective hydration of one of the allyl groups was also achieved

Continuous Flow Process for Carbonyl and α,β-Unsaturated Carbonyl Compounds Reduction Using NaBH₄ Solutions: Toward Implementation of Luche Reduction in Flow

Carbonyl reductions using NaBH4 are generally high-yielding and highly selective processes commonly used in organic synthesis and the pharmaceutical industry. However, the reaction is exothermic, and the stability of the NaBH4 solution is limited, resulting in long reaction times at a controlled temperature in batch reactors, which are costly and energy-intensive on a large scale. Due to the low solubility of NaBH4 or lack of stability of NaBH4 solution in protic solvents, this reducing agent is underutilized in flow synthesis. In this work, efficient reductions of ketones and aldehydes are reported for the first time in a continuous advanced-flow reactor using stabilized solutions of NaBH4 within short residence times (between 20 and 80 s) at 60 °C. This methodology was also successfully applied to perform a straightforward and easy-to-handle continuous chemoselective reduction of α,β-unsaturated carbonyl compounds in the presence of cerium(III) chloride in methanol (i.e., Luche reduction)

Molecular versus Ionic Structures in Adducts of GaX₃ with Monodentate Carbon-Based Ligands

A molecular donor–acceptor adduct has been isolated by the reaction of the <i>N</i>-heterocyclic carbene 1,3-dimethyl imidazol-2-ylidene (diMe-IMD) with GaCl₃. In contrast, the structurally related, yet much more nucleophilic, 1,3-dimethyl-2-methylene-2,3-dihydro-1<i>H</i>-imidazole (diMe-MDI) gave rise to ion pairs of type [L₂GaX₂]­[GaX₄], where X = Cl, Br, or I. With IBioxMe₄, a <i>N</i>-heterocyclic carbene that is more nucleophilic than diMe-IMD, the outcome of the reaction was dependent on the nature of the halide. Ionic 1:1 adducts between monodentate ligands and GaX₃ salts have only one precedent in the literature. The peculiar behavior of carbon-based ligands was explained on the basis of their electronic properties and reaction kinetics