been measured for the α-metallation of some arylmethanes, of 5H-dibenzo[a,d]cycloheptene and its dihydro derivative, free and complexed with tricarbonylchromium, by potassium hydride in tetrahydrofuran in the presence of 18-crown-6 ether. The stable solutions of the complexed anions have been studied by 13C NMR spectroscopy. With the free ligands the kinetic acidity depends upon the structure to a
在18-crown-6存在下,通过氢化钾在四氢呋喃中测量了一些芳基甲烷,5 H-二苯并[ a,d ]环庚烯及其二氢衍生物(与三羰基铬络合)的α-金属化速率常数。醚。通过13 C NMR光谱研究了络合阴离子的稳定溶液。对于游离配体,动力学酸度在很大程度上取决于结构,但是在相应的配合物中,金属化的速率没有明显变化。根据13 C化学位移数据,建议在芳基甲基和二苯并噻吩基阴离子的电子结构之间存在相似性,这将说明它们的金属化速率非常相似。
Transformation of Trifluorotoluenes Triggered by Titanium(IV) Chloride-Catalyzed Hydrodefluorination using Hydrosilanes
作者:Takayuki Yamada、Kodai Saito、Takahiko Akiyama
DOI:10.1002/adsc.201500920
日期:2016.1.7
The titanium tetrachloride‐catalyzed hydrodefluorination reaction of trifluorotoluene derivatives was developed using triethylsilane as the reducing agent. The reaction produced various toluene derivatives with high chemoselectivities by means of readily accessible reagents. This hydrodefluorination process was extended to the intramolecular Friedel–Crafts benzylation reaction, furnishing polycyclic