An Arylative Ring Expansion Cascade of Fused Cyclobutenes via Short-Lived Intermediates with Planar Chirality

An arylative ring expansion cascade has been developed for the synthesis of medium-sized carbocycles from fused cyclobutenes. This reaction proceeds through a short-lived <i>cis</i>,<i>trans</i>-cycloalkadiene intermediate that is formed by thermal 4π electrocyclic ring opening. Chirality transfer experiments provide direct evidence for the transient generation of the intermediate

Synthesis of π‑Extended Fluoranthenes via a KHMDS-Promoted Anionic-Radical Reaction Cascade

An unprecedented KHMDS-promoted domino reaction to furnish hydroxyfluoranthenes is described. Biaryl compounds bearing acyl and naphthylalkenyl moieties are transformed into 9-hydroxydibenzo­[<i>j</i>,<i>l</i>]­fluoranthenes in a single step through the formation of an aromatic and a pentagonal ring system. A variety of fluoranthenes including those with extended π-conjugation, a heteroaromatic ring, and unsymmetrical substituents could be synthesized. Mechanistic studies reveal a unique reaction cascade where KHMDS acts as both a base and a single-electron donor

An Arylative Ring Expansion Cascade of Fused Cyclobutenes via Short-Lived Intermediates with Planar Chirality

An arylative ring expansion cascade has been developed for the synthesis of medium-sized carbocycles from fused cyclobutenes. This reaction proceeds through a short-lived <i>cis</i>,<i>trans</i>-cycloalkadiene intermediate that is formed by thermal 4π electrocyclic ring opening. Chirality transfer experiments provide direct evidence for the transient generation of the intermediate

Synthesis of Functionalized Polycyclic Aromatic Compounds via a Formal [2 + 2]-Cycloaddition

A base-promoted formal [2 + 2]-cycloaddition of 2-acyl-2′-vinyl-1,1′-biaryls was developed to provide polycyclic cyclobutanols as a step toward the synthesis of substituted polycyclic aromatic hydrocarbons and their heterocyclic analogues

Synthesis and Properties of Tribenzocarbazoles via an Acid-Promoted Retro (2+2)-Cycloaddition of Azapropellanes

We describe herein the development of a new method to synthesize tribenzocarbazoles via an acid-promoted retro (2+2)-cycloaddition of azapropellanes, which were prepared by potassium hexamethyldisilazide (KHMDS)-promoted (2+2)-cycloaddition. The tribenzocarbazoles showed strong fluorescence both in solution and the solid state. The structural, electronic, and optical properties of the synthetic tribenzocarbazoles are also described

Synthesis and Properties of Tribenzocarbazoles via an Acid-Promoted Retro (2+2)-Cycloaddition of Azapropellanes

We describe herein the development of a new method to synthesize tribenzocarbazoles via an acid-promoted retro (2+2)-cycloaddition of azapropellanes, which were prepared by potassium hexamethyldisilazide (KHMDS)-promoted (2+2)-cycloaddition. The tribenzocarbazoles showed strong fluorescence both in solution and the solid state. The structural, electronic, and optical properties of the synthetic tribenzocarbazoles are also described

Synthesis and Properties of Tribenzocarbazoles via an Acid-Promoted Retro (2+2)-Cycloaddition of Azapropellanes

We describe herein the development of a new method to synthesize tribenzocarbazoles via an acid-promoted retro (2+2)-cycloaddition of azapropellanes, which were prepared by potassium hexamethyldisilazide (KHMDS)-promoted (2+2)-cycloaddition. The tribenzocarbazoles showed strong fluorescence both in solution and the solid state. The structural, electronic, and optical properties of the synthetic tribenzocarbazoles are also described

Development of a Brønsted Acid-Promoted Arene–Ynamide Cyclization toward the Total Syntheses of Marinoquinolines A and C and Aplidiopsamine A

A Brønsted acid-promoted arene–ynamide cyclization has been developed to construct the 3<i>H</i>-pyrrolo­[2,3-<i>c</i>]­quinolines. This reaction consists of the generation of a highly reactive keteniminium intermediate from arene–ynamide activated by a Brønsted acid and electrophilic aromatic substitution reaction to give arene-fused quinolines in high yields. This methodology enabled facile access to marinoquinolines A and C and aplidiopsamine A

Radical Aminomethylation of Imines

Taking advantage of the high level of performance of <i>N</i>-alkoxycarbonyl-imines, we achieved the first example of addition of the aminomethyl radical to imine. The reaction efficiency depended on the structure of the radical precursor, whether it is an iodide or a xanthate, and an electron-withdrawing group on the nitrogen atom of the radical. This reaction allows direct introduction of an N-substituted aminomethyl group onto imine to provide 1,2-diamine as well as the short-step synthesis of ICI-199,441

Striking Difference between Succinimidomethyl and Phthalimidomethyl Radicals in Conjugate Addition to Alkylidenemalonate Initiated by Dimethylzinc

We used dimethylzinc to develop a conjugate addition reaction of imidomethyl radicals to alkylidenemalonates, in which we observed a significant difference between succinimidomethyl and phthalimidomethyl radicals. This reaction provides new access to γ-aminobutyric acid derivatives, which often function as neurotransmitters