[3+3] Cyclocondensation of Disubstituted Biphenyl Dialdehydes: Access to Inherently Luminescent and Optically Active Hexa-substituted C3-Symmetric and Asymmetric Trianglimine Macrocycles

• Published in: Journal of organic chemistry Vol. 82; no. 5; pp. 2472 - 2480
• Main Authors: Wang, Zhenzhen, Nour, Hany F., Roch, Loic M., Guo, Minjie, Li, Wenjiao, Baldridge, Kim K., Sue, Andrew C. -H., Olson, Mark A.
• Format: Journal Article
• Language: English
• Published: WASHINGTON Amer Chemical Soc 03.03.2017
• Subjects: biphenyl; chemical reactions; chemical structure; Chemistry; Chemistry, Organic; imines; legs; Lewis bases; luminescence; nitrogen; organic chemistry; Physical Sciences; Science & Technology; X-ray diffraction; SCHIFF-BASE MACROCYCLES; LIGANDS; IMINES; COMPLEXES; TRIANGLAMINE MACROCYCLES; PROTONATION CONSTANTS; BASIS-SETS; CONFORMATION
• ISSN: 0022-3263; 1520-6904; 1520-6904
• DOI: 10.1021/acs.joc.6b02868

A general synthetic route to inherently luminescent and optically active 6-fold substituted C-3-symmetric and asymmetric biphenyl-based trianglimines has been developed. The synthesis of these hexa-substituted triangular macrocycles takes advantage of a convenient method for the synthesis of symmetrically and asymmetrically difunctionalized biphenyl dialdehydes through a convergent two-step aromatic nucleophilic substitution-one-pot Suzuki-coupling reaction protocol. A modular [3+3] diamine-dialdehyde cyclocondensation reaction between both the symmetrically and asymmetrically difunctionalized-4,4'-biphenyldialdehydes with enantiomerically pure (1R,2R)-1,2-diaminocyclohexane was employed to construct the hexa-substituted triangular macrocycles. B97-D/6-311G(2d,p) density functional theory determined structures and X-ray crystallographic analysis reveal that the six substituents appended to the biphenyl legs of the trianglimine macrocycles adopt an alternating conformation not unlike the 1,3,5-alternate conformation observed for calix[6]arenes. Reduction of the imine bonds using NaBH4 afforded the corresponding 6-fold substituted trianglamine without the need to alkylate the amine nitrogen atoms which could hinder their later use as metal coordination sites and without having to introduce asymmetric carbons.