Convergent synthesis

Convergent synthesis is a strategy for making a target molecule by preparing separate fragments independently and joining them late in the sequence. It can shorten routes when fragment assembly avoids long linear sequences.

Retrosynthetic analysis: A planning method that works backward from a target molecule to simpler precursors. It identifies bonds whose disconnection can divide the target into independently prepared fragments.
Linear synthesis: A synthetic route in which intermediates are made sequentially, with each step depending on the preceding one. A linear route can outperform convergence when the fragments are difficult to prepare or couple.
Natural product total synthesis: The laboratory construction of naturally occurring molecules from simpler chemical starting materials. Complex natural products often motivate convergent route designs.
Synthetic efficiency: The effectiveness of a chemical route in converting starting materials into a target with limited steps, waste, and effort. Convergent planning aims to improve route efficiency by preparing fragments in parallel.
Fragment coupling: A chemical reaction that joins two molecular fragments by forming a bond between them. This late-stage bond formation is the defining assembly step in a convergent route.
Modular synthesis: A strategy that builds molecules from interchangeable components through standardized assembly steps. Both strategies use component assembly, but modular synthesis emphasizes repeatable interchangeability.
Peptide synthesis: The chemical or biological formation of peptides by joining amino acid residues through peptide bonds. Peptides can be assembled from separately prepared segments using fragment coupling.
Chemical yield: The amount of product obtained from a chemical reaction relative to the maximum theoretical amount. A low-yielding fragment or assembly step can erase gains from a shorter sequence.
Protecting group: An atom or group temporarily attached to a molecule to prevent a reactive site from participating in a reaction. Independently prepared fragments may need protected functional groups to survive assembly conditions.
Divergent synthesis: A strategy that uses a shared intermediate to produce multiple distinct products through branching reaction sequences. It branches outward from a common precursor rather than combining separately prepared fragments.

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