Palladium(0)‐Catalyzed Synthesis of Cross‐Conjugated Polymers: Transformation into Linear‐Conjugated Polymers through the Diels–Alder Reaction

Making the shift : The title reaction of a propargylic bis(carbonate) with diboron compounds leads to new cross‐conjugated polymers 1 having 2,3‐butadienylene moieties. 1 is then converted into the linear‐conjugated polymers 2 through a Diels–Alder reaction. The fluorescent spectra of the cis ‐linked polymers 2 show large Stokes shifts compared to those of the cross‐conjugated polymer precursors  1 .