Synthesis, properties, and asymmetric catalysis of chiral cyclophanes and their metal complexes
- Author(s): Choi, So-Young Amy
- et al.
This dissertation has been devoted to the syntheses and studies of novel chiral, helical cyclophanes and their corresponding metal complexes. The subsequent part of the project involves the use of the copper complex of the chiral cyclophane 1 as an asymmetric catalyst in enantioselective organic transformation reactions. There are three chapters in this thesis. Chapter 1 describes the synthesis of chiral cyclophanes and their metal complexes. Racemic spirobiindanol (±)-6 was initially synthesized and resolved using literature methods. Metal-binding ligands were synthesized from each enantiomer, and Williamson ether synthetic method was used to obtain desired helical cyclophanes 1-5. Metal ions, such as silver(I), copper(I), mercury(II), zinc(II), and palladium(II), were used to form metal complexes of these cyclophanes. Chapter 2 discusses structures and properties of both cyclophanes and their metal complexes using spectral data from NMR, MS, UV, CD and X-ray crystallography. Lastly, Chapter 3 describes the use of a copper complex of the cyclophane 1 as an asymmetric catalyst for cyclopropanation of styrene with diazoester and for allylic oxidation of cycloalkenes, otherwise known as the Kharash-Sosnovsky reaction. The cyclopropanation reaction favored the formation of trans- phenylcyclopropane carboxylate in ̃ 20 % ee (68-87 % yield), and the allylic oxidation reactions produced the (R)-allylic carboxylate with ̃16 % ee (< 80 % yield)