Development of High- and Low-valent Early Transition Metal Catalysts for Carbon-Carbon Bond Forming Reaction

点击翻译按钮获取中文摘要

We developed a novel oxidant-free cross dehydrogenative coupling reaction of 2,6-lutidine and internal alkynes leading to five-membered carbocyclic compounds by non-metallocene cationic hafnium alkyl complexes. We also found that mild and salt-free reduction of MCl_5 (M=Nb, Ta) was achieved by using 3,6-bis(trimethylsilyl)-1,4-hexadiene derivatives as reducing reagents. The salt contact free low-valent TaCl_3 exhibits high catalytic activity for the trimerization of ethylene to 1-hexene (>1000 TOF) with excellent selectivity (>98%).