What is anti stereoselective?
Stereoselectivity. When an alkene undergoes addition, two new s bonds are formed. If we think of an alkene as having two faces, then the two new s bonds can either both form on the same face, which we call syn addition, or they can be formed on different faces which we call anti addition.
What is stereoselective and stereospecific?
A stereospecific mechanism specifies the stereochemical outcome of a given reactant, whereas a stereoselective reaction selects products from those made available by the same, non-specific mechanism acting on a given reactant.
What is the difference between stereoselective and regioselective?
The key difference between regioselectivity and stereoselectivity is that regioselectivity refers to the formation of one positional isomer over another, whereas stereoselectivity refers to the formation of one stereoisomer over another.
What is syn and anti?
When two atoms are added to the same side, it’s a syn relationship; when two atoms are added to opposite sides it’s an anti relationship.
Is sn2 stereoselective?
S N2 Reactions Are Stereospecific The SN2 reaction is stereospecific like other concerted reactions.. A stereospecific reaction is one in which different stereoisomers react to give different stereoisomers of the product.
How do you know if a reaction is stereoselective?
If more than one reaction could occur between a set of reactants under the same conditions giving products that are stereoisomers and if one product forms in greater amounts than the others, the overall reaction is said to be stereoselective.
Is E1 stereospecific or stereoselective?
Unlike E2 reactions, E1 is not stereospecific. Thus, a hydrogen is not required to be anti-periplanar to the leaving group.
Why is halogenation anti?
As a nucleophile, the halogen is attracted to partially positive carbon atoms in the bridged molecule. The resulting product has 2 halogens attached on opposite sides or ‘anti’ to each other. Since carbon can only have 4 bonds, this attack forces carbon to let go of the bridge halogen, thus breaking the bridge.
What is the difference between syn and CIS?
The difference is subtle: “cis” and “trans” implies that the orientation of the two groups is locked; you can’t convert cis to trans through rotation. The terms “syn” and “anti” imply similar relationships to “cis” and “trans”, but can also be applied to systems which are not locked.
How is SN2 stereoselective?
The SN2 reaction Consider a reaction being carried out on starting materials that are stereoisomeric, e.g. a pair of enantiomers. If the reaction gives a product from one of the starting materials that is a stereoisomer of the product from the other, then the reaction is deemed to be stereospecific.
Why is a reaction not stereoselective?
The first reaction gives no preference to one stereoisomer or the other. So, it’s NOT stereoselective. Since the stereochemical relationship between the products in the reaction is enantiomers, we can also call this reaction enantioselective.