Organoborane-mediated synthesis

Another method for preparing functional Ziegler-Natta polymers is to use an organoborane mediated synthesis. This method has been extensively studied and reviewed by Chung . The success of this technique results from these factors (a) trialkyl boranes are Lewis acids, which are stable to Z-N catalysts, (b) they are soluble in Z-N (hydrocarbon) solvents, (c) they are remarkably versatile synthons for a variety of functional groups. In this case, borane functional alpha olefin monomers (31) are polymerized to polyboranes which can be hydrolyzed to a variety of functional groups. 

In the above-described pChemTec project, a combination of miniplant and micro structured reactor plant equipment is used for the organoborane synthesis as an example for a future production facility for fine chemicals. This approach differs from the usual application of a miniplant as a mediator between laboratory-scale and pilot plant-scale operation. The microstructured reactor plant shown in Figure 4.47, a combination with a typical miniplant set-up, exhibits greater complexity than the miniplant but it nevertheless consumes a much smaller proportion of the volume of the plant set-up. 

Novel Silyl-mediated 10-TMS-9-BBD Organoborane Reagents for Asymmetric Synthesis... 

Chapter 3 by Jie Jack Li presents a collection of very interesting total syntheses of naturally occurring indole alkaloids where palladium chemistry plays a central role in the syntheses. Five different types of palladium-mediated reactions are treated (I) oxidative cyclization reactions promoted by palladium (II) species (2) transmetallation reactions with organoboranes, organoslannanes, and organozinc reagents (3) inter- and intramolecular Heck reactions (4) reactions with it-allylpalladium as the intermediate and (5) reactions using C-N bond formation as the key step for the synthesis. 

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