申请人:Zhao Yigang
公开号:US20100145060A1
公开(公告)日:2010-06-10
Embodiments of the invention provide a method of using Schwartz Reagent, Cp
2
Zr(H)Cl, without accumulating or isolating it. Methods provide mixtures of Cp
2
ZrCl
2
, reductants that selectively reduce Cp
2
ZrCl
2
, and substrates. After reaction of Cp
2
ZrCl
2
and the reductant, an intermediate reduction product is formed, apparently Schwartz Reagent. The in situ Schwartz Reagent then selectively reduces certain functional groups on the substrate. Substrates include tertiary amides, tertiary benzamides, aryl O-carbamates, and heteroaryl N-carbamates, which are reduced to aldehydes, benzaldehydes, aromatic alcohols, and heteroaromatics, respectively. Compared to prior methods, reagents are inexpensive and stable, reaction times are short, and reaction temperature in certain cases is conveniently room temperature. It has been estimated that using the in situ method described herein instead of synthesized or commercially obtained Schwartz Reagent provides a 50% reduction in cost.
本发明的实施例提供了一种使用Schwartz试剂,Cp2Zr(H)Cl的方法,而无需积累或隔离它。方法提供了Cp2ZrCl2的混合物,选择性还原Cp2ZrCl2的还原剂,以及底物。在Cp2ZrCl2和还原剂发生反应后,形成了一个中间还原产物,显然是Schwartz试剂。然后,原位的Schwartz试剂选择性地还原底物上的某些官能团。底物包括三级酰胺、三级苯酰胺、芳基O-氨基甲酸酯和杂环N-氨基甲酸酯,它们分别被还原为醛、苯甲醛、芳香醇和杂环化合物。与先前的方法相比,试剂价格低廉且稳定,反应时间短,某些情况下的反应温度方便地为室温。据估计,使用本文描述的原位方法而不是合成或商业获得的Schwartz试剂可使成本降低50%。