Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

Abstract

The diastereoselective oxazoline-directed lithiation of calix[4]arenes is reported with diastereoselective ratios of greater than 100:1 in some instances. Notably, it has been found that the opposite diastereomer can be accessed via this approach merely through the choice of an alkyllithium reagent. The inherently chiral oxazoline calix[4]arenes have also been preliminarily examined as ligands in the palladium-catalyzed Tsuji–Trost allylation reaction, returning results comparable to their planar chiral ferrocene counterparts pointing towards future application of these types of compounds.

Keywords

• calix[4]arene
• inherently chiral
• ortholithiation
• oxazoline
• Tsuji–Trost