Enantiopure C₁-Cyclotriveratrylene with a Reversed Spatial Arrangement of the Substituents

Abstract

Cyclotriveratrylene (CTV) is a macrocyclic cyclophane presenting a bowlshaped conformation, used as building block to construct cryptophane and hemicryptophane capsules. A method to synthesize new enantiopure CTV derivatives with an unprecedented spatial arrangement of their substituents, exhibiting C 1 symmetry, is described. The absolute configuration was assigned by ECD spectroscopy coupled with modeling. A statistical model has allowed for optimization of the proportion of C 1 CTV, and the modularity of this approach is also highlighted.

Synthesis, resolution, and chiroptical properties of hemicryptophane cage controlling the chirality of propeller arrangement of a C3 triamide unit

“…This level of theory was indicated by us earlier as the preferred one for capturing electronic chiroptical properties of CTV systems. 31,32 The calculated spectrum is in line with experimental one in the range of 190 to 260 nm, which involves 1 L a and 1 L b…”

“…ECD spectrum of 1 was calculated for an arbitrary chosen M‐ enantiomer using hybrid functional CAM‐B3LYP with the SVP basis set and PCM model for CH 3 CN. This level of theory was indicated by us earlier as the preferred one for capturing electronic chiroptical properties of CTV systems . The calculated spectrum is in line with experimental one in the range of 190 to 260 nm, which involves 1 L a and 1 L b transitions.…”

Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

“…Chiral derivatives result when the aromatic residues carry either one, three or two different additional substituents which reduces the symmetry from C 3 v to either C 3 or C 1 (Scheme 1) [14–16].…”

Enantiopure cryptophane derivatives: Synthesis and chiroptical properties

“…In a recent study, Martinez and coworkers reported an original approach to synthesize C 1symmetric CTB derivativess. 40 The initial C 3 -symmetry was broken by inverting the positions of two alkoxy groups on one of the aromatic rings (Figure 10). A mixture of C 1 -(25) and C 3 -symmetric (26) CTB compounds was obtained by the cyclization of the two appropriate regio-isomers using scandium triflate, in a total yield of 51%.…”

“…While most of the described CTB derivatives possess C 3 ‐ or C 3v ‐symmetry, C 1 ‐symmetric trimers are more challenging to obtain and little contribution has been reported in this field. In a recent study, Martinez and co‐workers reported an original approach to synthesize C 1 ‐symmetric CTB derivativess 40 . The initial C 3 ‐symmetry was broken by inverting the positions of two alkoxy groups on one of the aromatic rings (Figure 10).…”