Oligomeric isoflavonoids. Part 4. Synthesis of the daljanelin class of isoflavonoid-neoflavonoid dimers

A protocol of introducing an electrophilic C-1 fragment to a pterocarpan nu cleus, followed by anionic coupling of a C-6-C-2 benzofuranoid precursor an d late introduction of the final C-6 fragment, permitted the syntheses of d aljanelins B 3 and D 5. The feasibility of introducing the same electrophil ic C-1 fragment to C-2 of the pterocarpan moiety to obtain a precursor to d aljanelin A 2 was also demonstrated.