The synthesis of homochiral ligands based on [2.2]paracyclophane

A new ortho-lithiation of homochiral 4-N,N-diethylamido[2.2]paracyclophane 8 is the key to the production of a wide variety of 4,5-disubstituted homochiral ligands. ψ-Geminal bromination of 8 proceeds in high yields and the resulting bromide may be converted into a variety of 4,13-disubstituted ligands. The o-lithiation and ψ-geminal reactions can be used sequentially to give 4,5,12-trisubstituted compounds in which two liganding groups have the same geometrical relationship as in ‘Phanephos’™. Homochiral oxazolines with only planar chirality have been made, one of which has been shown to be an effective catalyst for the Heck reaction.