22substitution

22substitution is a term used in the field of organic chemistry to describe a specific type of substitution reaction. It refers to the replacement of a hydrogen atom in a molecule by a 22-substituent, which is typically a group that contains a double bond and a hydrogen atom. This reaction is often used to introduce functional groups into organic compounds, making it a valuable tool in synthetic chemistry.

The 22substitution reaction typically involves the use of a base, such as sodium hydride or lithium diisopropylamide, to deprotonate the hydrogen atom that is to be replaced. This generates a carbanion, which is then attacked by the 22-substituent. The reaction proceeds via an SN2 mechanism, where the carbanion attacks the substrate from the backside, leading to the formation of a new carbon-carbon bond.

One of the key features of 22substitution is its stereospecificity. The reaction occurs with inversion of configuration at the carbon atom that is being substituted, meaning that the new stereocenter formed has the opposite configuration to the starting material. This makes 22substitution a useful tool for the synthesis of enantiomerically pure compounds.

In summary, 22substitution is a valuable reaction in organic synthesis, allowing for the introduction of functional groups and the formation of new carbon-carbon bonds. Its stereospecificity makes it a powerful tool for the synthesis of enantiomerically pure compounds.