Synthesis of enantiopure planar chiral bis-(para)-pseudo-meta-type [2.2]paracyclophanes

Risa Sawada; Masayuki Gon; Jun Nakamura; Yasuhiro Morisaki; Yoshiki Chujo

doi:10.1002/chir.23010

Synthesis of enantiopure planar chiral bis-(para)-pseudo-meta-type [2.2]paracyclophanes

Chirality. 2018 Oct;30(10):1109-1114. doi: 10.1002/chir.23010. Epub 2018 Aug 20.

Authors

Risa Sawada¹, Masayuki Gon¹, Jun Nakamura², Yasuhiro Morisaki^{1

2}, Yoshiki Chujo¹

Affiliations

¹ Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
² Department of Applied Chemistry for Environment, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan.

PMID: 30126002
DOI: 10.1002/chir.23010

Abstract

A new type of planar chiral (R_p )- and (S_p )-4,7,12,15-tetrasubstituted [2.2]paracyclophanes was prepared from racemic 4,7,12,15-tetrabromo[2.2]paracyclophane as the starting substrate. Regioselective lithiation and transformations afforded racemic bis-(para)-pseudo-meta-type [2.2]paracyclophane (4,15-dibromo-7,12-dihydroxy[2.2]paracyclophane). Its optical resolution was performed by the diastereomer method using a chiral camphanoyl group as the chiral auxiliary. The diastereoisomers were readily isolated by simple silica gel column chromatography, and the successive hydrolysis afforded (R_p )- and (S_p )-bis-(para)-pseudo-meta-type [2.2]paracyclophanes ((R_p )- and (S_p )-4,15-dibromo-7,12-dihydroxy[2.2]paracyclophanes). They can be used as pseudo-meta-substituted chiral building blocks.

Keywords: chiral auxiliary; chiral building block; diastereomer; optical resolution; regioselectivity.

Publication types

Research Support, Non-U.S. Gov't