Synthesis of an Optically Active Poly(para‐phenylene) Ladder Polymer

A chiroptically active compound without a helical structure has been constructed in the ladder polymer 1 (R = 3.4-C6H3(OC6H13)2), which has been synthesized from the corresponding enantiomerically pure OC10H20O-bridged diboronic acid. The molar ellipticity of 1 [2.2 × 106 rad cm2mol−1 (461 nm)] leads to an anisotropy factor of g = 0.003, which is thus only an order of magnitude less than the maximum value (0.02) for chiral conjugated polymers so far reported.