Iron-Catalyzed Amide Formation from the Dehydrogenative Coupling of Alcohols and Secondary Amines
作者:Elizabeth M. Lane、Katherine B. Uttley、Nilay Hazari、Wesley Bernskoetter
DOI:10.1021/acs.organomet.7b00258
日期:2017.5.22
substituents on the amine or alcohol substrate. Variable-temperature NMR spectroscopic studies suggest that the catalyst resting state is an off-cycle iron(II) methoxide species, (iPrPN(H)P)Fe(H)(OCH3)(CO), resulting from addition of methanol across the Fe–N bond of (iPrPNP)Fe(H)(CO). This reversibly formed iron(II) methoxide complex is favored at mild temperatures but eliminates methanol upon heating
五配位氢化铁(II)络合物(i Pr PNP)Fe(H)(CO)(i Pr PNP = N [CH 2 CH 2(P i Pr 2)] 2)选择性催化醇和仲胺的脱氢分子间偶联以形成叔酰胺。这是迄今为止报道的最高效的脱氢酰胺化贱金属催化剂,在某些情况下可实现高达600的营业额。该催化剂对空间上不需要的胺和醇或环状底物效果很好,并且在从甲醇合成甲酰胺中特别有效。然而,随着胺或醇底物上大取代基的引入,催化剂性能迅速下降。变温NMR光谱研究表明,催化剂静止状态是关断周期铁(II)甲醇物种,(我镨PN(H)P)的Fe(H)(OCH 3)(CO),是由于在(i Pr PNP)Fe(H)(CO)的Fe–N键上添加了甲醇。这种可逆形成的甲醇铁(II)配合物在温和的温度下很受青睐,但加热时会消除甲醇。