Tiara[5]arenes (T[5]s), a new class of five‐fold symmetric oligophenolic macrocycles that are not accessible from the addition of formaldehyde to phenol, were synthesized for the first time. These pillar[5]arene‐derived structures display both unique conformational freedom, differing from that of pillararenes, with a rich blend of solid‐state conformations and excellent host–guest interactions in solution. Finally we show how this novel macrocyclic scaffold can be functionalized in a variety of ways and used as functional crystalline materials to distinguish uniquely between benzene and cyclohexane.

Stereolabile pillar[5]arene derivatives, which are dynamic racemic mixtures in solution on account of their low inversion barriers, were employed as platforms to study chiral symmetry breaking during crystallisation.

To investigate the dynamic stereochemical inversion behavior of pillar[5]arenes (P[5]s) in more detail, we synthesized a series of novel rim-differentiated P[5]s with various substituents and examined their rapid rotations by variable-temperature NMR (203–298 K). These studies revealed for the first time the barrier of “methyl-through-the-annulus” rotation (Δ G ‡ = 47.4 kJ·mol –1 in acetone) and indicated that for rim-differentiated P[5]s with two types of alkyl substituents, the smaller rim typically determines the rate of rotation. However, substituents with terminal C=C or C≡C bonds give rise to lower inversion barriers, presumably as a result of attractive π–π interactions in the transition state. Finally, data on a rim-differentiated penta-methyl-penta-propargyl P[5] exhibited the complexity of the overall inversion dynamics.

An efficient and regioselective palladium(II)‐catalyzed [5+2] annulation of unprotected o‐indoloanilines with internal alkynes under microwave irradiation has been explored. The diverse imine‐containing 1,2‐fused indole[1,7‐a]diazepines are constructed in moderate to excellent yields. The mechanistic pathway shows pivalic acid and molecular oxygen to play crucial roles for the regeneration of highly active electrophilic palladium species in the catalytic cycle.magnified image

A "rim-differentiated" pillar[6]arene ) was obtained successfully, with the assistance of a dimeric silver trifluoroacetate template, among eight different constitutional isomers in a direct and regioselective manner. The solid-state conformation of this macrocycle could switch from the 1,3,5-alternate to a truly rim-differentiated one upon guest inclusion. This highly symmetric RD-P[6] not only hosts metal-containing molecules inside its cavity, but also can form a pillar[6]arene-C 60 adduct through co-crystallization on account of donor-acceptor interactions. The development of synthetic strategies to desymmetrize pillararenes offers new opportunities for engineering complex molecular architectures and organic electronic materials.

A sequential single-flask multicomponent reactions is highly effective for the synthesis of 1,2-dihydroisoquinolines through amidealkylation from intermediate N-acylisoquinolinium salts under mild conditions. N-Acylisoquinolinium ions and trichloromethyl-1-(1H-indol-3-yl)isoquinoline-2(1H)-carboxylate have demonstrated their reactivity toward aromatic and aliphatic π-nucleophiles. One of the 1,2-dihydroisoquinoline derivatives was found to be a potent inhibitor for transcription factor NF-κB by blocking IκBα degradation, p65 nuclear translocation, and NF-κB DNA binding in TNF-α-induced NIH 3T3 cells.

Tiara[5]arenes (T[5]s), a new class of five‐fold symmetric oligophenolic macrocycles that are not accessible from the addition of formaldehyde to phenol, were synthesized for the first time. These pillar[5]arene‐derived structures display both unique conformational freedom, differing from that of pillararenes, with a rich blend of solid‐state conformations and excellent host–guest interactions in solution. Finally we show how this novel macrocyclic scaffold can be functionalized in a variety of ways and used as functional crystalline materials to distinguish uniquely between benzene and cyclohexane.

A facile and efficient synthesis of novel oxo, thio and seleno hydantoin fused tetrahydroazepino [4,5-b]indoles was reported.