Synthesis, functionalization, and isolation of planar-chiral pillar[5]arenes with bulky substituents using a chiral derivatization agent

Talal F Al-Azemi; Mickey Vinodh; Fatemeh H Alipour; Abdirahman A Mohamod

doi:10.1039/c9ra03135a

Synthesis, functionalization, and isolation of planar-chiral pillar[5]arenes with bulky substituents using a chiral derivatization agent

RSC Adv. 2019 Jul 26;9(40):23295-23301. doi: 10.1039/c9ra03135a. eCollection 2019 Jul 23.

Authors

Talal F Al-Azemi¹, Mickey Vinodh¹, Fatemeh H Alipour¹, Abdirahman A Mohamod¹

Affiliation

¹ Chemistry Department, Kuwait University P. O. Box 5969, Safat 13060 Kuwait t.alazemi@ku.edu.kw +965-2481-6482 +965-2498-554.

Abstract

Bulky perneopentyloxy-pillar[5]arene (Pillar-1) was synthesized and its conformational mobility was investigated using variable-temperature ¹H NMR spectroscopy. The host-guest interactions between Pillar-1 and n-octyltrimethylammonium hexafluorophosphate (OMA) were investigated, and the formation of a 1 : 1 complex was revealed via ¹H NMR. Planar-chiral isomers were synthesized via the reaction of a hydroxy-functionalized pillar[5]arene with chiral derivatization agent (S)-(+)-MTPA-Cl. The (Sp, R)-and (Rp, R)-forms of the pillar[5]arene diastereomers were isolated by HPLC, and their structures were analyzed by ¹⁹F NMR. HPLC measurements indicated that racemization did not take place at 40 °C for 72 h.