Cleavage of Ether, Ester, and Tosylate C(sp<sup>3</sup>)–O Bonds by an Iridium Complex, Initiated by Oxidative Addition of C–H Bonds. Experimental and Computational Studies
作者:Sabuj Kundu、Jongwook Choi、David Y. Wang、Yuriy Choliy、Thomas J. Emge、Karsten Krogh-Jespersen、Alan S. Goldman
DOI:10.1021/ja312464b
日期:2013.4.3
A pincer-ligated iridium complex, (PCP)Ir (PCP = κ(3)-C6H3-2,6-[CH2P(t-Bu)2]2), is found to undergo oxidative addition of C(sp(3))-O bonds of methyl esters (CH3-O2CR'), methyl tosylate (CH3-OTs), and certain electron-poor methyl aryl ethers (CH3-OAr). DFT calculations and mechanistic studies indicate that the reactions proceed via oxidative addition of C-H bonds followed by oxygenate migration, rather
发现钳形连接的铱络合物 (PCP)Ir (PCP = κ(3)-C6H3-2,6-[CH2P(t-Bu)2]2) 发生 C(sp(3) )-O 键的甲酯 (CH3-O2CR')、甲苯磺酸甲酯 (CH3-OTs) 和某些缺电子的甲基芳基醚 (CH3-OAr)。DFT 计算和机理研究表明,反应是通过 CH 键的氧化加成和氧化物迁移进行的,而不是通过直接添加 CO 进行。因此,甲基芳基醚通过添加甲氧基 CH 键进行反应,然后 α-芳基氧化物迁移得到顺式-(PCP)Ir(H)(CH2)(OAr),然后铱到亚甲基氢化物迁移得到( PCP)Ir(CH3)(OAr)。乙酸甲酯在甲氧基上发生 CH 键加成得到 (PCP)Ir(H)[κ(2)-CH2OC(O)Me],然后得到 (PCP-CH2)Ir(H)(κ(2)-O2CMe ) (6-Me) 其中甲氧基 CO 键已被裂解,来自甲氧基的亚甲基已迁移到 PCP