Halides amines, tert

Leeuwen and coworkers studied the kinetics for the amination of aryl triflates and bromides using different Xantphos catalyst systems. " For triflate amination, they found the rate to be first order in amine and ferf-butoxide, but zero order in aryl triflate. From this, they concluded that a mechanism similar to the upper pathway in Scheme 7 was operating, with the deprotonation of coordinated amine being the ratedetermining step. For aryl bromides, however, the rate was dependent on the concentration of iert-butoxide, but not amine or aryl bromide. Thus, under these conchtions, the lower pathway-with the replacement of halide by tert-butoxide as the rate-limiting step - was postulated to be the operating mechanism. 

Reaction of polyhalogenocarboxylic acid halides with tert. amines... 

Aryl Halide Amination. Phenothiazine has been coupled to 3,10-dibromoperylene under palladium catalysis and in the presence of tri-terf-butylphosphonium tetrafluoroborate and potassium tert-butoxide, affording the corresponding perylene-bridged diphenothiazine in modest yield (eq 15). ... 

Dehydrohalogenation (s. a. Ethylene derivatives from halides) CC Hal Dehydrohalogenation-rearrangement 16, 938 Deoxymercuration, stereospecific 16, 970 Dequaternization s. Amines, tert., from ammonium salts, quaternary Derivatives s. a. subentry derivatives... 

Allylic amines are coupled to halides giving either allylic amines or enamines depending on the reaction condition. Reaction of steroidal dienyl triflate with Boc-diprotected allylamine affords allylamine. Use of AcOK as a base is crucial for the clean coupling[102]. The tert-allylic amine 123 reacts with an aryl halide to give the enamine 125 in DMF and allylic amine 124 in nonpolar solvents[103]. 

A more recent publication by Weigand and Pelka has disclosed a polymer-bound Buchwald-Hartwig amination [40], Activated, electron-deficient aryl halides were coupled with conventional PS Rink resin under microwave irradiation. Subsequent acidic cleavage afforded the desired aryl amines in moderate to good yields (Scheme 7.22). Commercially available Fmoc-protected Rink amide resin was suspended in 20% piperidine/N,N-dimethylformamide at room temperature for 30 min to achieve deprotection. After washing and drying, the resin was placed in a silylated microwave vessel and suspended in dimethoxyethane (DME)/tert-butanol... 

Nolan reported the use of the 2,6-diisopropylphenyl imidazolium carbene precursor, which contains an unsaturated backbone, for the reaction of aryl chlorides with a variety of amines at 100 °C [165, 166]. This temperature is lower than those conventionally used for reactions of aryl chlorides, but is higher than those used with P(tBu)3 or the 2-biphenylyl di-tert-butylphosphines. Reaction yields were high when 2 mol % palladium was used. Reactions of primary amines occurred in good yield, even when unhindered aryl halides were used. The monoarylamine was obtained in 86 % yield, and only a 5 % yield of the diaryl-amine by-product was isolated. Notably, reactions of both aryl bromides and iodides proceeded at room temperature. 

The use of a strong base in the palladium-catalyzed amination of aryl halides precludes the use of many substrates, such as those with aromatic nitro groups or enolizable hydrogens, esters other than tert-butyl esters, and many substrates with base-sensitive stereochemistry such as some protected amino acids and heterocyclic substrates [191]. Thus, conditions that employ milder bases are required. A solution that involves reaction temperatures as low as those used for reactions conducted with sodium tert-butoxide has not been developed. However, carbonate and phosphate bases can be used with certain catalysts at reaction temperatures comparable to those of reactions involving the first- and second-generation catalysts. 

Thio analogs of these compounds, for example, PhP(S)(NHR)2 can also be prepared similarly, from the corresponding thiophosphonic halides and amines or by oxidative addition of sulfur to diaminophosphines, RP(NR92 Phenylphosphonic acid diamides, PhP(Q)(NHBu )2 (Q = S, Se) were prepared from PhP(NHBfr)2 by oxidative addition of sulfur or selenium and the 0x0 derivative PhP(0)(NHBu )2 by oxidation with tert-butyl peroxide. Their lithiation produces unusual cyclic or polycyclic dUithium salts of the phosphonate dianions [PhP(Q)(NBfr)2] (Q = O, S, Se). The dimethylaluminum derivatives PhP(Q)(NBu )2AlMe2 (Q = S, Se) obtained from PhP(Q)(NHBu )2 with AlMes are fom-membered chelate rings. ... 

NaNHR, or NaNR2. Lithium dialkylamides also react with aryl halides to give the A-arylamine. With these reagents, the benzyne mechanism generally operates, so cine substitution is often found. The reaction of an amine, an aryl halide, and potassium tert-butoxide generates the A -aryl amine. A -Arylation was accomplished with butyllithium and a secondary amine using Ni/C-diphenylpho-sphinoferrocene (dppf). Ring closure has been effected by this type of reaction, as in the conversion of 16 to the tetrahydroquinoline. 

If secondary and tertiary amines are desired, only 2 to 3 moles of ammonia are used. Aqueous ammonia does not react to any extent at room temperature, owing to the immiscibility of halide and water. Industrially, aqueous ammonia is used and heated in an autoclave under pressure. Tertiary halides, as, for example, tert-butyl and tert- m.y bromides, do not yield amines, but yield olefines almost exclusively. The object of the present experiment is to illustrate the ammonolysis of alkyl halides. The ammonolysis of aryl halides cannot be easily accomplished in the laboratory, as it involves the use of high pressure, and temperatures of about 200°. Industrially the method is practical. 

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