Next Article in Journal
A Study on Security and Privacy Guidelines, Countermeasures, Threats: IoT Data at Rest Perspective
Next Article in Special Issue
Potentially Mistaking Enantiomers for Different Compounds Due to the Self-Induced Diastereomeric Anisochronism (SIDA) Phenomenon
Previous Article in Journal
Numerical Study of the Mechanical and Acoustic Emissions Characteristics of Red Sandstone under Different Double Fracture Conditions
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Symmetry
Volume 11
Issue 6
10.3390/sym11060773
symmetry-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Communication

Resolution and Racemization of a Planar-Chiral A1/A2-Disubstituted Pillar[5]arene

by
Chao Xiao
1,
Wenting Liang
2,
Wanhua Wu
1,*,
Kuppusamy Kanagaraj
1,
Yafen Yang
3,
Ke Wen
3,* and
Cheng Yang
1,*
1
College of Chemistry and Healthy Food Evaluation Research Center, Sichuan University, Chengdu 610064, China
2
Institute of Environmental Sciences, Department of Chemistry, Shanxi University, Taiyuan 030006, China
3
Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai 201210, China
*
Authors to whom correspondence should be addressed.
Symmetry 2019, 11(6), 773; https://doi.org/10.3390/sym11060773
Submission received: 16 May 2019 / Revised: 31 May 2019 / Accepted: 4 June 2019 / Published: 9 June 2019
(This article belongs to the Special Issue Chiral Auxiliaries and Chirogenesis II)
Browse Figures
Versions Notes

Abstract

Butoxycarbonyl (Boc)-protected pillar[4]arene[1]-diaminobenzene (BP) was synthesized by introducing the Boc protection onto the A1/A2 positions of BP. The oxygen-through-annulus rotation was partially inhibited because of the presence of the middle-sized Boc substituents. We succeeded in isolating the enantiopure RP (RP, RP, RP, RP, and RP)- and SP (SP, SP, SP, SP, and SP)-BP, and studied their circular dichroism (CD) spectral properties. As the Boc substituent is not large enough to completely prevent the flip of the benzene units, enantiopure BP-f1 underwent racemization in solution. It is found that the racemization kinetics is a function of the solvent and temperature employed. The chirality of the BP-f1 could be maintained in n-hexane and CH2Cl2 for a long period at room temperature, whereas increasing the temperature or using solvents that cannot enter into the cavity of BP-f1 accelerated the racemization of BP-f1. The racemization kinetics and the thermodynamic parameters of racemization were studied in several different organic solvents.
Keywords: pillar[5]arene; planar chirality; chiral resolution; racemization kinetics; supramolecular chemistry pillar[5]arene; planar chirality; chiral resolution; racemization kinetics; supramolecular chemistry
Graphical Abstract

Share and Cite

MDPI and ACS Style

Xiao, C.; Liang, W.; Wu, W.; Kanagaraj, K.; Yang, Y.; Wen, K.; Yang, C. Resolution and Racemization of a Planar-Chiral A1/A2-Disubstituted Pillar[5]arene. Symmetry 2019, 11, 773. https://doi.org/10.3390/sym11060773

AMA Style

Xiao C, Liang W, Wu W, Kanagaraj K, Yang Y, Wen K, Yang C. Resolution and Racemization of a Planar-Chiral A1/A2-Disubstituted Pillar[5]arene. Symmetry. 2019; 11(6):773. https://doi.org/10.3390/sym11060773

Chicago/Turabian Style

Xiao, Chao, Wenting Liang, Wanhua Wu, Kuppusamy Kanagaraj, Yafen Yang, Ke Wen, and Cheng Yang. 2019. "Resolution and Racemization of a Planar-Chiral A1/A2-Disubstituted Pillar[5]arene" Symmetry 11, no. 6: 773. https://doi.org/10.3390/sym11060773

APA Style

Xiao, C., Liang, W., Wu, W., Kanagaraj, K., Yang, Y., Wen, K., & Yang, C. (2019). Resolution and Racemization of a Planar-Chiral A1/A2-Disubstituted Pillar[5]arene. Symmetry, 11(6), 773. https://doi.org/10.3390/sym11060773

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop