Each step usually involves reaction at only one chemical bond in the molecule.
In planning the route of chemical synthesis, chemists usually visualize the end product and work backward toward increasingly simpler compounds.
Finally, the scope of this transformation was expanded beyond aryl substituted acetylenes with the benzannulation of silyl-haloacetylenes (Chapter 4).
These products readily generate 2-naphthynes with the addition of cesium fluoride and can be oligomerized or cyclized to isolate substituted ortho-naphthalenes.
These compounds serve as synthetically useful building blocks for further derivatization and iterative benzannulation to access sterically crowded substrates (Chapter 2).
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Despite the high efficiency of this reaction, phenylene ethynylene macrocycles prove to be too rigid to undergo complete benzannulation (Chapter 3).How do chemists decide the chemical route they will use to prepare a compound? Retro means going backward therefore in planning their synthesis, chemists start from the compound they want to make and cut it in smaller pieces, going backward, until they can reach the starting material they want to use (something they can easily buy and that is not too expensive).Each of these smaller pieces corresponds to at least one reaction (or step).This dissertation describes recent advances in methodology to access novel aromatic architectures using a benzannulation strategy (Chapter 1).Silyl protected acetylenes are readily reacted to yield the corresponding 2-naphthylsilane.This process is illustrated below: In chemistry, the synthesis of most compounds of interest (Drugs, polymers, dyes…) cannot be done in a single step.Some synthesis are relatively short (2-4 steps), others can be very long (35-55 steps).For example, paracetamol (IUPAC: N-(4-hydroxyphenyl) ethanamide), a relatively simple molecule, can be prepared in one, two or three steps depending on the starting material you choose (what chemists call starting material is the very first chemical compound they will use to start a synthesis, the one they will use in the first step (or reaction) of the synthesis they want to make).Taxol (an anti-cancer drug) is a natural compound with a very complex structure whose total synthesis requires at least 40 steps.Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! It is the process by which many substances important to daily life are obtained.It is applied to all types of chemical compounds, but most syntheses are of organic molecules.