作者:Ryuhei Ikeda、Ryoichi Kuwano
DOI:10.1002/chem.201600732
日期:2016.6.13
enantiomeric ratio (e.r.). Chiral cis‐isoxazolidines were obtained in up to 89:11 e.r., with no formation of their trans isomers, when the substrates had a primary alkyl substituent at the 5‐position. The mechanistic studies indicate that the hydridoiridium(III) species prefers to deliver its hydride to the C5 atom of the isoxazole ring. The hydride attack leads to the formation of the chiral isoxazolidine via
在H 2存在下,铱催化剂[IrCl(cod)] 2-膦-I 2(cod = 1,5-环辛二烯)选择性地将三氟甲磺酸异恶唑鎓还原为异恶唑啉或异恶唑烷。当使用旋光性膦-恶唑啉配体时,铱催化的氢化反应以高至良好的对映选择性进行。将3-取代的5-芳基异恶唑鎓盐转化为4-异恶唑啉,对映体比例高达95:5(er)。手性顺式-异唑烷类化合物的最高获得时间为89:11,没有形成反式异构体,当底物在5位上具有伯烷基取代基时。机理研究表明,氢化铱(III)物种倾向于将其氢化物传递到异恶唑环的C5原子上。氢化物侵蚀导致3-异恶唑啉中间体形成手性异恶唑烷。同时,在4-异恶唑啉的选择性形成中,5-芳基取代基的空间位阻可能会阻碍C5原子处的氢化物攻击。