Synthesis and Characterization of a New Thiophene-Bridged Diamidophosphine [NPN] Donor Set and Its Coordination Chemistry with Zirconium(IV): Unexpected Deprotonation−Lithiation Sequence with a Mesitylaminothiophene Precursor
作者:Gabriel Ménard、Howard Jong、Michael D. Fryzuk
DOI:10.1021/om900612n
日期:2009.9.14
complexes are presented. The ligand precursor [NPN]SH2 was prepared from N-(2,4,6-Me3C6H2)(3-NH-4-Br-SC4H2) (1), tBuLi, and PhPCl2 in Et2O in 50% yield; the stereochemistry of the ligand precursor was unexpected and likely resulted from a competitive bromine−lithium exchange and deprotonation sequence with the thiophene starting material 1 and tBuLi. A mechanism to rationalize the observed stereochemistry
噻吩桥联的二氨基膦膦配体[NPN] S H 2(2)(其中[NPN] S H 2 = [ N-(2,4,6-Me 3 C 6 H 2)(3-提出了NH-SC 4 H 2 -2-)] 2 PPh})以及几种[NPN] S ZrX 2(X = NMe 2,Cl,I)配合物。配体前体[NPN] S H 2由N-(2,4,6-Me 3 C 6 H 2制备)(3-NH-4-Br-SC 4 H 2)(1),t BuLi和PhPCl 2在Et 2 O中的产率为50%;配体前体的立体化学是出乎意料的,可能是由于与噻吩原料1和t BuLi竞争性的溴-锂交换和去质子序列。在氘化实验之后,提出了一种合理化所观察到的产物立体化学的机理。[NPN] S Zr(NMe 2)2(8)可以通过[NPN] S H 2和Zr(NMe)的直接反应制备,产率为80%。2)4在甲苯中。[NPN] S ZrCl 2(9)和[NPN]