The flexible synthesis of tetra- and triarylethenes bearing different aryl groups has been a long-standing challenge in organic synthesis. Here we report a palladium-catalysed syn-diarylation of arylethynyl N-methyliminodiacetyl (MIDA) boronates. The products, triarylalkenyl N-methyliminodiacetyl boronates, allow a step-economic and modular synthesis of tetra- or triarylethenes via a subsequent stereospecific Suzuki-Miyaura coupling reaction or base-promoted protodeborylation, respectively. Use of the sp³-B(MIDA) masked aryl alkyne is the key factor for success by offering an exceptionally good regioselectivity for the boron-retentive coupling. The unusual regioselectivity is believed to arise from the stabilization due to the strong electron donation from the C−Pd σ bond to the p-orbital of boron in the transition state of migratory insertion. A broad range of differently substituted tetra- and triarylethenes are constructed in good yields and geometrical control. Synthetic manipulation of the C-B bond also enables the facile construction of several other types of tetra-substituted alkenes.

带有不同芳基的四芳基和三芳基的柔性合成一直是有机合成中的长期挑战。在这里，我们报道了钯催化的芳基乙炔基N-甲基亚氨基二乙酰基（MIDA）硼酸酯的合成二芳基化。产物三芳基烯基N-甲基亚氨基二乙酰基硼酸酯可分别通过随后的立体有规Suzuki-Miyaura偶联反应或碱促进的原脱硼藻酸逐步经济地和模块化地合成四或三芳烃。sp ^3的使用-B（MIDA）掩盖的芳基炔烃是成功的关键因素，它为硼-保持性偶联提供了极佳的区域选择性。据信，由于迁移插入过渡态中C-Pdσ键向硼的p轨道的强电子给体，稳定化产生了异常的区域选择性。大量的不同取代的四芳基和三芳基醚以良好的收率和几何形状控制而构建。CB键的合成操纵还使得能够容易地构造其他几种类型的四取代的烯烃。