Olefination acyclic amines

Imide-terminated telechelics are also synthesized by metathesis depolymerization, and it is found that phthalimide-substituted olefins allow for productive depolymerization when only one methylene spacer separates the nitrogen atom and the olefin (Fig. 8.21). This combination of steric hindrance around the nitrogen lone pair and decreased electron donation from resonance prevents the negative neighboring group effect. However, secondary acyclic amines are unable to produce telechelics through metathesis depolymerization because of unfavorable catalyst-amine interactions. 

The carbonylation of the sp3 C-H bond adjacent to a nitrogen atom is also possible by means of chelation-assisted C-H bond activation.121 The carbonylation reaction of A-(2-pyridyl)pyrrolidine occurs at the a-position of the pyrrolidine ring by using [RhCl(cod)]2 as a catalyst and 2-propanol as a solvent. Cyclic amines exhibit a high reactivity (up to 84%) (Equation (93)), while acyclic amines show relatively low reactivity (18%). The use of Ru3(CO)i2 as a catalyst does not result in a carbonylation reaction, but instead the addition of the sp3 C-H bond across the olefin bond to give an alkylation product, as mentioned before (Section 10.05.4). 

Evidence for the syn elimination mechanism was obtained by the decomposition of threo and erythro derivatives of 2-amino-3-phenylbutane.8 The threo isomer 9 reacts predominantly to give the cis conjugated alkene 10 in a selectivity of 400 to 1. For the erythro form 11, the trans isomer 12 is favoured by a ratio of at least 20 to 1. The threo isomer 9 also reacts more readily due to the lower steric pressure in the transition state. In general, acyclic amines could undergo elimination to form either a cis or trans olefin, but the more stable trans form is obtained.2... 

The telomerization of butadiene by means of water in ILs was described by Dullius et Rottger et al. report a process for the telomerization of acyclic olefins having at least two conjugated double bonds, or their mixtures, using a palladium-carbene complex as catalyst in an IL solvent. The nucleophiles included water, alcohols, phenols, polyols, carboxylic acids, ammonia and primary and secondary amines. The acycylic olefins could be either 1,3-butadiene or isoprene. 

Despite the fact that polar entities are catalyst poisons, a variety of acyclic olefins containing a heteroatom functional group can undergo metathesis in the presence of a suitable catalyst, although at a high catalyst level. These include unsaturated esters, ethers, ketones, amines, nitriles, halogens, etc. [14]. In particular metathesis reactions - including ethenolysis - of unsaturated fatty esters and fatty oils are of interest, as they have perspectives for the oleochemical industry [15]. 

J.K. Cha et al. developed a stereocontrolled synthesis of bicyclo[5.3.0]decan-3-ones from readily available acyclic substrates. Acyclic olefin-tethered amides were first subjected to the intramolecular Kulinkovich reaction to prepare bicyclic aminocyclopropanes. This was followed by a tandem ring-expansion-cyclization sequence triggered by aerobic oxidation. The reactive intermediates in this tandem process were aminium radicals (radical cations). The p-anisidine group was chosen to lower the amine oxidation potential. This substituent was crucial for the generation of the aminium radical (if Ar = phenyl, the ring aerobic oxidation is not feasible). 

Kresze and coworkers have found about a three order of magnitude rate increase in imino ene reactions when an N-tosyl group is replaced with an N-perfluoroalkanesulfonyl moiety [87]. Thus, with the glyoxylate ester-derived imine and the one from chloral 255 as the enophiles, reactions with acyclic olefins are very rapid and occur at room temperature [Eq. (60)]. In these ene reactions one stereoisomeric homoallylic amine 256 was typically generated, although the stereochemistry was not elucidated. However, in one reported case a 1 1 mixture of diastereomers was obtained. Mechanistic studies based upon kinetic isotope effects seem to indicate that this reaction may in fact be a two-step process rather than a concerted one [87b]. 

A particularly useful general method for the synthesis of saturated nitrogen- and oxygen-containing partially unsaturated heterocycles, from 5-membered to medium ring-sized, is the Grubbs olefin metathesis applied, for example, to acyclic diaUcenyl-amines, as illustrated by syntheses of a dihydropyrrole and a tetrahydropyridine. ... 

Specific examples of the hydroaminomethylations of olefins with secondary amines are shown in Equations 17.19-17.21. Cyclic and acyclic secondary amines occur in high yield with linear-to-branched ratios exceeding 50 to 1 in most cases when catalyzed by the rhodium complex generated from [Rh(COD)JBF and xantphos. The reaction of pen-tene with piperidine is shown in Equation 17.19. These reactions are also compatible with alcohol (Equation 17.20) and acetal functional groups (Equation 17.21). 

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