Eidgenössische Technische Hochschule Zürich , Vladimir-Prelog-Weg 3, HCI H335, 8093 Zürich, Switzerland.
J Am Chem Soc. 2017 Mar 15;139(10):3603-3606. doi: 10.1021/jacs.6b12421. Epub 2017 Mar 7.
Experimental mechanistic studies of iridium-catalyzed, enantioselective allylic substitution enabled by (phosphoramidite,olefin) ligands are reported. (η-Allylic alcohol)iridium(I) and (η-allyl)iridium(III) complexes were synthesized and characterized by NMR spectroscopy as well as X-ray crystallography. The substrate complexes are catalytically and kinetically competent to be intermediates in allylic substitutions of branched, racemic allylic alcohols with various nucleophiles. In addition, we have identified an off-cycle pathway involving reversible binding of molecular oxygen to iridium, which contributes to the air tolerance of the catalyst system.
报告了（膦酰胺、烯烃）配体促进的铱催化对映选择性烯丙基取代的实验机理研究。通过 NMR 光谱和 X 射线晶体学合成并表征了（η-烯丙醇）铱（I）和（η-烯丙基）铱（III）配合物。这些底物配合物在支链、外消旋烯丙醇与各种亲核试剂的烯丙基取代反应中具有催化和动力学能力的中间体。此外，我们还确定了一条涉及分子氧与铱可逆结合的非循环途径，这有助于催化剂体系的空气耐受性。
