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For example, the synthesis of paracetamol typically requires three separate reactions. Divergent synthesis starts with a common intermediate, which branches into multiple final products through distinct reaction pathways. Convergent synthesis synthesis involves the combination of multiple intermediates synthesized independently to create a ...
When many reactions need to be run in an array (such as the 96 reactions described in one of Armstrong's MCC arrays), some of the more tedious aspects of synthesis can be automated to improve efficiency. This work, the "DIVERSOMER method" was pioneered at Parke-Davis in the early 1990s to run up to 40 chemical reactions in parallel. These ...
One example of a synthesis reaction is the combination of iron and sulfur to form iron(II) sulfide: + Another example is simple hydrogen gas combined with simple oxygen gas to produce a more complex substance, such as water.
In another example, the Nicolaou's total synthesis of Taxol uses this reaction, although coupling stops with the formation of a cis-diol, rather than an olefin. Optimized procedures employ the dimethoxyethane complex of TiCl 3 in combination with the Zn(Cu). The first porphyrin isomer, porphycene, was synthesised by McMurry coupling. [8]
This reaction has been used successfully to probe for azides in living systems, even though the reaction rate is somewhat slower than that of the CuAAC. Moreover, because the synthesis of cyclooctynes often gives low yield, probe development for this reaction has not been as rapid as for other reactions.
The Ugi reaction has been applied in combination with an intramolecular Diels-Alder reaction [16] in an extended multistep reaction. A reaction in its own right is the Ugi–Smiles reaction with the carboxylic acid component replaced by a phenol. In this reaction the Mumm rearrangement in the final step is replaced by the Smiles rearrangement. [17]
Suppose the yield is 50% for each reaction; the overall yield of D is only 12.5% from A. In a convergent synthesis A → B (50%) C → D (50%) B + D → E (25%) the overall yield of E (25%) looks much better. Convergent synthesis is applied in the synthesis of complex molecules and involves fragment coupling and independent synthesis. This ...
The products of the Stetter reaction, 1,4-dicarbonyls, are valuable moieties for the synthesis of complex molecules. For example, Trost and coworkers employed a Stetter reaction as one step in their synthesis of rac-hirsutic acid C. [24] The intramolecular coupling of an aliphatic aldehyde with a tethered α,β-unsaturated ester led to the ...