Synthesis of Symmetrical Dinitro- and Diamino-Substituted Tröger's Base Analogues

Unveiling Route for the Synthesis of Tröger's Bases Through Azide Rearrangement

This study introduces a novel method for producing Tröger's bases by utilizing the rearrangement chemistry of benzyl azide. This method offers a convenient and adaptable pathway for synthesizing these important molecular structures with potential for further advancements. By reacting benzyl azide derivatives with TfOH under the presence of water, this process generates iminium ion, formaldehyde, and aniline intermediates in situ. Notably, this conversion is reversible under acidic conditions, allowing for the regeneration of the iminium ion and ultimately leading to the formation of the desired Tröger's base product. Additionally, this method could decrease the risk of exposure to an excess amount of formaldehyde.

Synthesis and Isolation of a Homochiral Nanohoop Composed of a Tröger's Base and Hexaparaphenylene

The synthesis of a new nanohoop containing a stereogenic Tröger's base skeleton tethered to a curved hexaparaphenylene ([6]CPP) is reported. The TB[6]CPP nanohoop possesses a stable C2 symmetrical structure, which promotes the allowed transition that gives rise to pale blue emission with a quantum yield of ~0.69, surpassing the value of the more symmetrical [8]CPP. Moreover, TB[6]CPP shows chiroptical properties including circular dichroism and circularly polarized luminescence with a moderate dissymmetry factor (|glum|) of ~2.1×10-3.

Design and Synthesis of a Novel Banana-Shaped Functional Molecule via Double Cross-Coupling

A novel banana-shaped molecule using 2,8-Dimethyl-6H,12H-5,11-methanodibenzo [b,f] [1,5]diazocine (Tröger's base) as bent-core was synthesized via double Carbon-Carbon cross-coupling reaction. The double Sonogashira cross-coupling reaction was optimized by using Pd(PPh₃)₂Cl₂ as catalyst, CuI as cocatalyst and diisopropylamine as base in place of triethylamine. The structure of this compound was confirmed by ¹H-NMR, ¹³C-NMR, Fourier transform infrared (FT-IR) spectroscopy and mass spectrometry.

Hünlich base derivatives as photo-responsive Λ-shaped hinges

The azo derivatives of the Hünlich base are introduced as a set of molecular switches with unique shapes and properties.

Accessing N-Stereogenicity through a Double Aza-Michael Reaction: Mechanistic Insights

Further development of the chemistry and applications of chiral compounds that possess configurationally stable stereogenic nitrogen atoms is hampered by the lack of efficient strategies to access such compounds in an enantiomerically pure form. Esters of propiolic acid and chiral alcohols were evaluated as cheap and readily available Michael acceptors in a diastereoselective synthesis of N-stereogenic compounds by means of a double aza-Michael conjugate addition. Diastereomeric ratios of up to 74:26 and high yields were achieved with (-)-menthyl propiolate as a substrate. Furthermore, a detailed mechanistic investigation was undertaken to shed some light on the course of this domino transformation. Kinetic studies revealed that the protic-solvent additive acts as a Brønsted acid and activates the ester toward the initial attack of the tetrahydrodiazocine partner. Conversely, acidic conditions proved unfavorable during the final cyclization step that provides the product.

Facile access to imidazole and imidazolium substituted dibenzo-diazocines

The C₂-symmetrical 2,8- and 4,10-diimidazo methano dibenzo diazocines were synthesized and converted into alkyl imidazolium salts.