C-AIkylation

Archibald, S.J., Alcock, N.W., Busch, D.H. and Whitcomb, D.R. (2000) Synthesis and characterization of silver(I) complexes with C-AIkyl functionahzed N,f/-Diphenylamidrnates Tetrameric and trrmeric structural motifs. Journal of Cluster Science, 11, 261—283. 

Diamino-5-benzylpyrimidines and analogues antibacterial agents. II. C-AIkylation of pyrimidines with Mannich bases and application to the synthesis of trimetoprim and analogues, J. Med. Chem.. 23,379. 1980 see also J. Med. Chem.. 23, 384 and 5.35. 1980. 

N-Substituted amidines react with MTIB to furnish cyclization products or the products of oxidative rearrangement. C-AIkyl-A(-arylamidine 392 cycUzes to give benzimidazole 393 in high yield, while C,A-diarylamidine 394 rearranges to give product 395 (Scheme 3.157) derived tfom an intermediate carbodiimide [479]. 

C-Alkylation of )8-Ketoester Enolates. Treatment of 1 with MeOTf in MeN02, followed by anion exchange with sodium tetraphenylborate gave the sulfoxonium salt 32 (eq 10). Reaction of this sulfoxonium salt with the 8-ketoester 33 provided a 3 1 mixture favoring the C-alkylated product 34 over the C -aIkylated material 35 (eq 11). ... 

An X-ray crystal structure analysis of frans-4-trimethylsilylcyclohexyl p-ni(r Kg sulphonate 67 reveals an elongated C(aIkyl)-0(ester) bond, compared to the non s wn substituted derivative . ... 

Dagegen verlauft die Reduktion der N-AIkyl-N-heteroaromaten-Salze nicht unter C-N-Spaltung (s. S. 242). 

The trans/gauche ratio also changes with the cation. A series of l-aIkyl-3-methylimidazolium (C mim, where n is the number of carbon atoms in the alkyl chain) cations generate RILs with [BF4] [15]. Figure 11 shows the Raman... 

Four 250 ml standard apparatus (round bottom flask, several inlets for stirrer, reflux condenser, nitrogen flux or vaccum, thermometer, heating bath) are filled each with 38 ml of distilled water and 405 mg (1.8 mmol) ammonium peroxodisuifate.To the fourth flask, additionally 90 mg of an alkylbenzene sulfonic acid sodium salt emulsifier (linear Cl 0-C13 aikyl chains, 70% in water) are added. After reaching an internai temperature of 80 °C,3 g of a monomer emulsion (prepared according toTabie 3.13) are added to each of the four batches. Within an induction phase of 15 min the reactions start. This is visuaiized by the pale blue coloration of the content of the flasks.Then the remaining monomer emulsion is added over a period of 3 h.The internal temperature has to be maintained at 80 °C during the whole reaction. After ail monomer emulsion has been added, the batches are heated at 80 °C for another 30 min.Then, the flasks are allowed to cool to room temperature. Now the reaction mixtures are adjusted to pH 8.5 by addition of 5% NaOH solution. 

Answer Let us assume that the halogen is chlorine. The olefinic bond is formed by removing a Cl and a H from two adjacent carbon atoms (olefinic carbons in product). To reconstruct the aikyl chloride required, we merely add a Cl and a H to the olefinic carbons of IJ-c. This can be done in two ways A and B. 

Answer lil-c is an aikyl dihalidc (Mirumo-3-chlorO 3- nethyibutane). 

What procedures are available for the preparation of b Answer Since D is an olefin, we must refer to Chapter II. Keeping in mind that the prescribed starting material is an aikyl halide, procedure II-I would be the method of choice. This would require an alkyl halide with the structure of C or D. CU3... 

Aikyl hnlicies are compounds containing halogen bonded to a saturated. sy -h,vl>ndiz< fl carbon atom. The C-X bond is polar, and alkyl halides can therefore behave as electrophiles. 

Many examples of such eliminations have now been seen for the f-block and for d metals. This type of /3-aIkyl elimination is recognized as an important chain transfer step in Ziegler-Natta and metallocene polymerization catalysis. When it occurs the polymer chain terminates in a C=C bond (equation 2) and in certain cases the aUcene chain end can undergo reinsertion and get back into the polymer growth... 

Fig. 18. Log tv against the log of the concentration of aikyl trimelhyl ammonium bromides of various chain lengths . C,e . C,j A, C (, 0> Cg , C4.. For comparison, data for potassium bromide is included. A- Radius of polystyrene latex particles = 48 nm. Reproduced with permission of American Chemical Society.

Table 9. Relaxation times (ns) for comb-like polymers in polar solvents at 25 °C (rjredO-38 cP) PMA poly(aIkyl methacrylates), n is the number of C-atoms in the alkyl chain...

Olah and Kuhn S found that fluorochloro-, fluorobromo- and fluoroiodo-alkanes are effective chloro-, bromo- and iodo-aikylating agents, respectively, in Friedel-Crafts alkylations of arenes in the presence of boron halide catalysts (equation 86). Boron trihalides catalyzq reactions of only the C—F bonds, but not of the C—Cl, C—Br or C—I bonds. The order of reactivity of the catalysts was found to be BI3 > BBr3 > BCI3 > BF3, and that of the carbon-halogen bonds C—F > C—Cl > C—Br > C—I. 

Coupling between C(s/ )-Organometallics and Primary Aikyl Halides... 

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