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SN2 Reactions

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krabi's version from 2015-06-11 02:42

Section

Question Answer
What is a polar Aprotic Solvent?Cannot Hydrogen bond. Cannot form ions. Therefore, increase Sn2 and inhibit Sn1.
What is solvolysis?When the actual solvent acts as a Nuc-.
Why are Sn1 boiled/reflux?To provide energy for the formation of the CC.
What 4 factors make a good Leaving Group?1) They are stable when they leave. 2) Weaker the base. 3) Electron withdrawing effects 4) Polarizability
How does the LG affect the Nuc-?The Leaving Group will always be more (stable) than a Nuc-
What are the differences between the Nucleophile and the 5 S’s?Substrate, Solvent, Speed, Stereochemistry & Skeleton Rearrangement
Compare the Sn1 & Sn2 re:Nucleophile.Sn2 needs a strong Nuc-, while Nuc doesnt affect Sn1. Sn2 X with a sterically hindered substrate. Sn2 requires a methyl/primary/secondary substrate; while Sn1needs a 2nd/3rd substrate.
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Section

Question Answer
Compare solventsA highly polar solvent ⇒ increases rx rate of Sn1 by stabalizing CC -- but slows down Sn2 by stabalizing to Nuc-
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Compare Speed: The Speed of Sn2 rx depends on k (of substrate & Nuc-) -- while speed of Sn1 depends on JUST the substrate.
Question Answer
Compare stereochemistrySn2 inverts the stereochemistry chiral centre -- while Sn1 makes racemic mixture
Compare carbon skeletonsCarbon skeleton rearrangement happens in Sn1, Sn2 has no skeletons in the closet.
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