Solid phase cross-coupling reaction of aryl(halo)silanes with 4-iodobenzoic acid
摘要:
Aryl(alkyl)(halo)silanes undergo facile and efficient palladium catalyzed cross-coupling reaction with iodobenzoic acid tethered to the Wang resin. Acid cleavage releases unsymmetrical biaryl carboxylic acids with high conversions, purities and yields. (C) 2001 Elsevier Science B.V. All rights reserved.
Oxidativedesulfurization-fluorination of methyl N-pyridyl(or N-pyrimidyl)-N-alkyldithiocarbamates gave the corresponding trifluoromethylamino-substituted pyridines (or pyrimidines), which underwent cross-coupling reaction to give a new type of liquid crystalline compounds having trifluoromethylamino group.
The reaction of poly(phenylmethylsiloxane) with α,β-unsaturated carbonylcompounds in the presence of aqueous K 2 CO 3 and 3 mol% of [Rh(OH)(cod)] 2 gives 1,4-conjugate addition product in good yields. Arylchlorosilanes also undergo the conjugate addition in excellent yields under similar conditions.
聚(苯基甲基硅氧烷)与 α,β-不饱和羰基化合物在 K 2 CO 3 水溶液和 3 mol% [Rh(OH)(cod)] 2 的存在下反应,以良好的产率得到 1,4-共轭加成产物. 芳基氯硅烷也在类似条件下以优异的产率进行共轭加成。
Syntheses and Properties of Novel Liquid Crystals Containing a Trifluoromethylamino Group
Liquid crystals (LCs) containing a trifluoromethylamino group are prepared by the cross-coupling reaction of p-bromo-substituted-(hetero)aryl(trifluoromethyl)amines that are derived from the corresponding dithiocarbamates through oxidative desulfurization–fluorination. The novel LCs are shown to exhibit mainly a smectic phase over a wide range of temperatures. Their electro-optical properties as a component of nematic LCs are compared with those of the corresponding methylamines.
The palladium catalyzed cross-coupling reaction of aryl halides with aryl(halo)silanes (halogen= F, Cl) gives good yields of unsymmetrical biaryls and p-terphenyls. The reaction takes place smoothly in N,N-dimethylformamide in the presence of an appropriate palladium catalyst and potassium fluoride. Since this reaction is tolerant of a variety of reactive functional groups, highly functionalized 4,4'-, 3,4'-, 2,4'- and even sterically crowded 2,2'-disubstituted biaryls can be obtained in moderate to high yields. The synthetic utility of the method has been demonstrated by its application to a short synthesis of liquid crystals. Mechanistic aspects of transmetalation of an aryl(fluoro)silicate intermediate with a palladium complex are discussed on the basis of the substituent effects on the rate of the cross-coupling reactions.
NaOH-Promoted cross-coupling reactions of organosilicon compounds with organic halides: Practical routes to biaryls, alkenylarenes and conjugated dienes
The use of NaOH has been found to be extremely effective in promoting the palladium-catalyzed cross-coupling reactions of aryl and alkenylchlorosilanes with organic halides such as aryl bromides and chlorides under very mild conditions. Copyright (C) 1996 Elsevier Science Ltd