Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany.
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-1569, USA.
Angew Chem Int Ed Engl. 2019 Jan 21;58(4):1088-1093. doi: 10.1002/anie.201811927. Epub 2018 Dec 20.
An enantioselective ring-closing C(sp )-H amination of 2-azidoacetamides is catalyzed by a chiral-at-metal ruthenium complex and provides chiral imidazolidin-4-ones in 31-95 % yield, with enantioselectivities of up to 95 % ee, and at catalyst loadings down to 0.1 mol % (turnover number (TON)=740). To our knowledge, this is the first example of a highly enantioselective C(sp )-H amination with aliphatic azides. Mechanistic experiments reveal the importance of the amide group, which presumably enables initial bidentate coordination of the 2-azidoacetamides to the catalyst. DFT calculations show that the transition state leading to the major enantiomer features a better steric fit and favorable π-π stacking between the substrate and the catalyst framework.
手性金属钌配合物催化的 2-叠氮乙酰胺的对映选择性环 closing C(sp )-H 氨化反应，在催化剂负载量低至 0.1mol%时（周转数（TON）=740），以 31-95%的收率和高达 95%ee 的对映选择性，提供手性咪唑烷-4-酮。据我们所知，这是首例具有脂肪族叠氮化物的高对映选择性 C(sp )-H 氨化反应。机理实验表明酰胺基团的重要性，它可能使 2-叠氮乙酰胺最初以双齿配位的方式与催化剂配位。密度泛函理论（DFT）计算表明，导致主要对映异构体的过渡态具有更好的空间适应性和底物与催化剂骨架之间有利的 π-π 堆积。
