The enantioselective synthesis of chiral Z-olefins is an important but challenging topic in organic chemistry. Iridium-catalysed Z-retentive asymmetric allylic substitution reactions have recently emerged as a promising strategy for trapping thermodynamically less stable anti-π-allyliridium intermediates. However, detailed mechanistic knowledge about this process has remained elusive. Here we report the structural characterization and transformations of the previously assumed putative anti-π-allyliridium intermediates. These complexes are highly efficient catalysts that enable Z-retentive asymmetric allylic alkylation of oxindoles accommodating a wide substrate scope. An iridium catalyst with a different metal-to-ligand ratio from that of a similar catalyst reported in the literature has been found to be crucial for regioselective nucleophilic attack at the less substituted allylic terminus. This simple yet powerful approach lays a solid foundation towards a general platform for the enantioselective synthesis of chiral Z-olefins.

手性Z-烯烃的对映选择性合成是有机化学中一个重要但具有挑战性的课题。铱催化的Z保留不对称烯丙基取代反应最近已成为一种有前途的策略，用于捕获热力学不太稳定的抗-π-烯丙基铱中间体。然而，关于这个过程的详细机械知识仍然难以捉摸。在这里，我们报告了先前假定的抗-π-烯丙基铱中间体的结构特征和转化。这些络合物是高效催化剂，可使Z- oxindoles 的保留不对称烯丙基烷基化，可适应广泛的底物范围。已发现具有与文献中报道的类似催化剂不同的金属配体比的铱催化剂对于在较少取代的烯丙基末端的区域选择性亲核攻击是至关重要的。这种简单而强大的方法为手性Z-烯烃的对映选择性合成的通用平台奠定了坚实的基础。