Synthesis of oligomers including eight P-chiral centers and the construction of the 12-phosphacrown-4 skeleton

The optically active oligomers, (S,R,R,S)-2, (S,R,S,R,R,S,R,S)-3, and 12-phosphacrown tetraborane 4, were synthesized by a stepwise oxidative coupling reaction. The behaviors of these optically active oligomers in the solid state and in solution were investigated in detail.