Click Chemistry and Homogeneous Catalysis

The Sonogashira cross-coupling of bromoalkenes is a useful method for making C—C bonds to terminal acetylenes [161]. It tolerates a variety of functional groups, and is catalyzed by a combination of Pd and Cu, through a cuprous acetylide intermediate. 

(a) Explain how the bite angle and the flexibility of a bidentate ligand are related to 

Nickel-triarylphosphite complexes catalyze the dimerisation of butadiene to cyclooctadiene. Cyclododecatriene is an unwanted by-product, which results from trimerization catalyzed by the same catalyst. Table 3.2 shows the product yields using various ligand-metal complexes (the remainder in each case is a tarry polymeric material). 

You are in charge of scaling up an asymmetric oxidation process for making 10 tpa (tons per annum) of a pharmaceutical intermediate which sells at 5000 ( 6750) per kg. The lab-scale reaction uses 2 mol% of a Ru-ligand complex as a catalyst and DMSO as solvent. List the factors you must consider when planning your scaleup operation. How would your list change if the product were a polymerization additive with a market price of 50 ( 67) per kg  

1 Anderson, J.G., Margitan, J.J. and Stedman, D.H. (1977) Atomic chlorine and the chlorine monoxide radical in the stratosphere three in situ observations. Science, 198, 501. 

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