Tolerance functional

Besides the possibility for nefarious effects due to steric hindrance, it should also be pointed out that due to the involvement of strong bases or acids (as in the modified version), the Pfitzinger is limited to substrates with tolerant functionalities. 

Each of these polymers exploit the ability of the group 10 metal catalysts used to tolerate functional groups and to copolymerise norbomene monomers bearing esters etc. into the polymer backbone. In the case of low-k dielectric polymers (Avatrel ) low levels (2-10 mol %) of 5-triethoxysilylnorbomene are used to impart good adhesive properties, the remaining 90+% of the monomer being a 5-alkylnorbomene. The alkylnorbomene is selected to tailor... 

Thus, it is possible to obtain tailored nanofibers from appropriately functionalized p-quaterphenylenes. A requirement for generating aligned nanofibers still seems to be muscovite mica as growth substrate, but the molecular basis is not restricted to p6P a para-phenylene molecular basis can be employed which tolerates functional groups at the para-positions. 

As regards the use of chloramine as aminating agent, dimethylalkylboranes have been used to prevent the loss of two alkyl residues [68,69]. This reaction tolerates functionality in the oiganoborane, but the yields decrease dramatically for a steri-cally demanding IV-chloralkylamine. 

Unlike early transition metal polymerization catalysts which do not tolerate functional groups, cationic palladium complexes are able to copolymerize ethylene with methyl acrylate.128... 

Stability Good Coking is problematic but the catalyst can be readily regenerated Catalysts do not readily tolerate functional groups or vinylidenes Catalysts are more tolerant of certain functionalities Some catalysts can tolerate functionality alkylidenes undergo thermal and chemical decomposition... 

The range of substrates which have been oxidized by activated dimethyl sulfoxide covers a wide range of tolerant functional groups, and there are many reports of how these oxidations proved superior to others that were investigated. 

The Ni complex incorporating mixed-donor P/O-ligands find industrial application in the Shell Higher Olefin Process (SHOP) to yield a-alkenes, while the complex (71) has been shown to be active in the polymerization of olefins and will also tolerate functionalized monomers such as methyl methacrylate. Grubbs and coworkers have adapted the standard SHOP catalyst to yield a highly active family of catalysts (eg. 72) for the polymerization of low-branched polyethylene. This is in contrast to the diimine catalysts (Section 5.2) which lead to a more highly branched polyethylene. 

The protonolysis reaction tolerates functionalities such as halide or ether groups in the alkylborane. However, p-dialkylaminoalkylboron compounds undergo elimination to give alkenes under these conditions (see Section 3.10.1.2). ° " Also, systems which are intrinsically labile to either acid or heat, such as some terpenoids, may give problems. For example, enantiomerically pure limonene produces 1 -men-thene which is substantially racemized on hydroboration-protonolysis (Scheme 15). 

Authorization to charge fees for performance of tolerance functions. 

Each of these polymers exploit the ability of the nickel and palladium catalysts described above to tolerate functional groups and to copolymerize norbornene monomers bearing esters etc. into the polymer backbone. 

Complex 2 is still regarded as the best catalyst for the polymerization of hydrocarbon ADMET monomers and monomers containing oflier tolerated functional groups, if the monomers can be rendered rigorously dry and oxygen-free. The ac-... 

The dose escalation with overdose control (EWOC) is a Bayesian approach similar to CRM. It is a dose-escalation scheme based on controlling the probability of overdosing a patient and not on targetting toxicity between 20% and 30% of the MTD, as in the original CRM (41,42). This method, like CRM, sequentially modifies the dose-response curve by including the information of all the patients previously included in the trial, but in this case, the dose-effect relationship deals with a two-parameter model, which can be considered as a tolerance function between two bounds (d iin and dnmx) ... 

In a very useful modification, simple ketones with CH2 adjacent to the carbonyl (cyclic ketones work much better than acyclic ketones) and ortfto-iodo-arylamines react under palladium catalysis to give indoles directly. The use of dimethylformamide as solvent and DABCO as the base are crucial to the success of the route. Mechanistically, the sequence certainly proceeds through the enamine. As well as being conceptually and practically simple, this method tolerates functional groups that would be sensitive to the acid of the traditional Fischer sequence. This method can also be applied to aldehydes, thus providing a direct route to 2-unsubstituted indoles, including side-chain-protected tryptophans. ... 

DiaryImethanols. Zinc in combination with the (dppe)NiBr2 complex mediates the reaction between aryl bromides and aromatic aldehydes. This process tolerates functional groups such as ketone, ester, amide, and nitrile. 

The use of protecting groups in polymerization is the preferred laboratory method for preparing many functional polymers. Protecting group methods have allowed the synthesis of otherwise difficult to synthesize functional and reactive polymers. Industrial applications are expected to be more in the specialty rather than commodity polymer area because of the costs associated with the protection and deprotection steps. For exanple, FMC has just announced a new line of protected functional anionic initiators for use in specialty block polymer synthesis. Commodity polymer applications will have to await the development of new catalysts that not only tolerate functionality but also incorporate it in a single step. 

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