The ‘lactone method’: enantioselective preparation of novel P,N-biaryl ligands and their use in the synthesis of the biarylic alkaloids, ancistrotanzanine B and ancistroealaine A

The ‘lactone method’ is a versatile tool for the atroposelective synthesis of axially chiral biaryls. The potential and scope of the concept are highlighted, in particular with respect to its use in the preparation of natural products and chiral auxiliaries. As a new application, the synthesis of novel axially chiral phosphineamines in enantiopure form is described; these ligands were used in the asymmetric Suzuki cross coupling of the molecular portions of the biarylic natural products ancistrotanzanine B and ancistroealaine A.