Design of Highly Selective Alkyne Hydrothiolation Rh<sup>I</sup>-NHC Catalysts: Carbonyl-Triggered Nonoxidative Mechanism
作者:Laura Palacios、Yoann Meheut、María Galiana-Cameo、María José Artigas、Andrea Di Giuseppe、Fernando J. Lahoz、Victor Polo、Ricardo Castarlenas、Jesús J. Pérez-Torrente、Luis A. Oro
DOI:10.1021/acs.organomet.7b00251
日期:2017.6.12
deprotonation of the thiol to generate the RhI active species, whereas the π-acceptor character of the carbonyl ligand hinders the oxidative addition process. In addition, the stereochemistry of the key thiolate-π-alkyne intermediate, which is determined by the electronic preference of the carbonyl ligand to coordinate cis to IPr, facilitates the rate-limiting alkyne thiometalation step.
已经制备了带有N,O-吡啶-2-甲醇-(NO)二齿配体的新的Rh I -IPr(IPr = 1,3-双(2,6-二异丙基苯基)咪唑啉-2-卡宾)配合物。羰基配合物Rh(NO)(IPr)(CO)有效催化一系列炔烃的氢硫醇化反应,对α-乙烯基硫化物具有高选择性。反应性研究和DFT计算揭示了一条新的非氧化催化途径,该途径通过Rh I催化中间体,这是由吡啶-2-甲醇基和羰基配体之间的相互作用驱动的。碱性烷氧基配体促进巯基的去质子化以生成Rh I活性物种,而羰基配体的π受体特性阻碍了氧化加成过程。另外,关键的硫醇盐-π-炔中间体的立体化学是由羰基配体的电子偏好决定,以将顺式配位至IPr,这有利于限速炔硫金属化步骤。