Ligand‐Controlled Diastereoselective Cobalt‐Catalysed Hydroalkynylation of Terminal Alkynes to
<i>E</i>
‐ or
<i>Z</i>
‐1,3‐Enynes
作者:Sebastian M. Weber、Jona Queder、Gerhard Hilt
DOI:10.1002/chem.202001697
日期:2020.9.21
A diastereoselective hydroalkynylation of terminal alkynes to form the head‐to‐head dimerization products by two different cobalt‐phosphine catalyst system is reported. The use of the bidentate ligand dppp and additional triphenylphosphine led to the selective formation of the (E)‐1,3‐enynes (E:Z>99:1) in good to excellent yields, while the tridentate ligand TriPhos led to the corresponding (Z)‐1,3‐enynes
据报道,通过两种不同的钴膦催化剂体系,末端炔烃的非对映选择性加氢烷基化反应形成了头对头二聚产物。双齿配体dppp和其他三苯基膦的使用导致选择性地形成(E) -1,3-烯炔(E:Z > 99:1),产率高至优异,而三齿配体TriPhos导致相应的(Z)‐1,3-炔烃,具有中等至良好的收率,具有出色的立体选择性(高达E:Z =1:99)。两种预催化剂都易于处理,因为它们在大气条件下具有稳定性。优化的反应条件是通过实验设计(DoE)方法确定的,该方法以前并未用于钴催化的反应优化中。美国能源部将所需的反应数量降至最低。