Re: tojc: steric hinderance
lietkeam@plu.edu
Thu, 12 Dec 1996 18:04:44 -0800 (PST)
Bryn-
Steric hindrance is a term referring to the availablity of space
surrounding an atom. In this course, that atom is usually carbon. When a
methyl, primary, or even a secondary molecule is used in Sn2 reaction,
the reaction proceeds extremely quickly because the nucleophile has at
least one spot by the carbon which is relatively open (due to the
hydrogen's small size), whereas in a tertiary molecule, the attached
groups are so bulky, they take up most of the space directly next to the
carbon, leaving no room for the electrons of the nucleophile to attract
the carbon. This concept can be demonstrated more clearly using a
molecular model set where the atoms are made to scale. I hope this helps
you understand this idea more clearly.
-ahna
On Thu, 12 Dec 1996 heathbm@plu.edu wrote:
> I have a question from awhile back that I have never understood. I know
> that primary halides react better in Sn2 reactions and that this is
> because of something called steric hinderance but I don't understand
> exactly what steric hinderance is and why is makes the primary halides
> more reactive and the tertiary halides less reactive.
>
> Bryn (heathbm@plu.edu)
>
>
>