通过反应,分别制备了新的笨重的三(三甲基甲硅烷基)甲硅烷基硼酸酯频哪醇和己二醇酯((TMS)3 Si–B(pin)和(TMS)3 Si–B(hg))。三(三甲基甲硅烷基)甲硅烷基钾与相应的硼亲电子试剂。值得注意的是,这些甲硅烷基硼酸酯在空气和硅胶中表现出很高的稳定性,可用于芳烃卤化物的无过渡金属硼取代,从而以高收率提供所需的硼化产物,并具有出色的B:Si比(高达96%的收率, B / Si = 99/1)。这些新的甲硅烷基硼酸酯还用于与各种芳基卤化物进行的顺序硼酸化/交叉偶联过程,以及用于苯乙烯的碱介导的硅烷化反应。
Room Temperature Palladium-Catalyzed Cross Coupling of Aryltrimethylammonium Triflates with Aryl Grignard Reagents
作者:Jonathan T. Reeves、Daniel R. Fandrick、Zhulin Tan、Jinhua J. Song、Heewon Lee、Nathan K. Yee、Chris H. Senanayake
DOI:10.1021/ol1018739
日期:2010.10.1
Aryltrimethylammonium triflates and tetrafluoroborates were found to be highly reactive electrophiles in the Pd-catalyzed cross coupling with aryl Grignard reagents. The coupling reactions proceed at ambient temperature with a nearly stoichiometric quantity of Grignard reagent, and diverse functionality is tolerated. Competition experiments established the reactivity of PhNMe3OTf relative to PhCl,
The invention relates to bimesogenic compounds of formula I
wherein R
11
, R
12
, MG
11
, MG
12
, X
11
, X
12
and Sp
1
have the meaning given in claim
1
, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.
method from commercially available aromatic halides has been used for the synthesis of a series of donor/acceptor para-substituted biphenyls, DC6H4C6H4A, where D is an electron donor group and A an electron acceptor group, which are of interest as liquid crystal precursors and as having potential in non-linear optics. Biaryls in which the donor-phenyl moiety is replaced by a 2-furyl or 2-thienyl can
The invention relates to bimesogenic compounds of formula I
wherein R
11
, R
12
, MG
11
, MG
12
, X
11
, X
12
and Sp
1
have the meaning given in claim
1
, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.
Synthèse de biaryles dissymétriques par électroréduction d'halogénures aromatiques catalysée par des complexes du nickel associé à la 2,2′-bipyridine
作者:Gilbert Meyer、Michel Troupel、Jacques Périchon
DOI:10.1016/0022-328x(90)87206-s
日期:1990.8
preparation of unsymmetrical biaryls by electroreduction of a mixture of two aryl halides which are para-substituted with electron acceptors and electron donors, respectively. The syntheses were carried out in N-methylpyrrolidone by constant current electrolyses in an undivided cell fitted with a sacrificial magnesium anode.