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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 ...
In the synthesis of a sublibrary the support is not divided and only one amino acid is coupled to the whole sample. As a result, one position is really occupied by the same amino acid in all components. For example, in the B2 sublibrary position 2 is occupied by the "yellow" amino acid in all the nine components.
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]
A multi-component reaction (or MCR), sometimes referred to as a "Multi-component Assembly Process" (or MCAP), is a chemical reaction where three or more compounds react to form a single product. [1] By definition, multicomponent reactions are those reactions whereby more than two reactants combine in a sequential manner to give highly selective ...
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]
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.
Reaction example of Chan–Lam coupling. Compound 1, a pyrrole, is coupled with aryl boronic acid, 2, to afford product 3, which is then carried forward to the target 4. The nitrile group of 2 does not poison the catalyst. Pyridine is the ligand used for the reaction. Although the reaction requires three days, it was carried out at room ...
The reaction can also be quenched with pyridine, which will scavenge ZnI 2 and excess reagents. [24] Methylation of heteroatoms is also observed in the Simmons–Smith reaction due to the electrophilicity of the zinc carbenoids. For example, the use of excess reagent for long reaction times almost always leads to the methylation of alcohols. [25]