The synthesis of a tetra‐functionalized pentaerythritol core decorated with N‐methyl‐N,N‐diphenylamine‐based push‐pull chromophores and its electropolymerization to 3D push‐pull networks are described. The electrochemical and absorption behaviors of the tetramer are compared with the one of two reference linear push‐pull compounds, carrying triphenylamine (TPA) or methyldiphenylamine (MeDPA) donor groups, a thienyl linker and a dicyanovinyl acceptor group (DCV). We found that substituting the outer phenyl with a methyl group causes important differences in the radical cation stability, such that MeDPA chromophore generates stable dimers and TPA is reversibly oxidized. Interestingly, DFT calculations suggest that steric hindrance and electrostatic interactions dominate the radical cation reactivity.
Divergent Pd-catalyzed reaction cascades with various 1,3-diynamides yielding either 2-amino-3-alkynylindoles or 2-amino-4-alkenylquinolines were established. Omitting or adding TBAF (tetrabutylammonium fluoride) to the reaction of N,N-(2-iodophenyl)(4-toluenesulfonyl)-1,3diynamides with secondary or primary amines in the presence of KOH in THF and catalytic amounts of Pd(PPh 3 ) 4 completely changed the outcome of the reaction. In the absence of TBAF, 2-amino-3-alkynylindoles were the sole products, while the presence of TBAF switched the product formation to 2-amino-4-alkenylquinolines. Deuterium labeling proceeded selectively at the C3 and C11 positions of the 2-amino-4alkenylquinoline products and this suggests the unprecedented formation of [4]cumulenimines from 1,3-diynamides as reactive key intermediates.
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