SN2 Mechanism

What does SN2 mechanism stand for?

Nucleophilic substitution

What are three required components for a SN2 reaction to occur?

Nucleophile, primary alkyl halide, and leaving group

SN2 is a CONCERTED mechanism. What does this mean?

No carbocation is formed

What is used to determine the rate law of a SN2 reaction?

rate=k[nucleophile][substrate]

What happens to the stereogenic center?

There is configuration inversion

What are two other facts about SN2 reaction?

-SN2 can only occur on sp3 hybridized carbons

-SN2 CANNOT occur on vinyl and aril halides

What four factors influence the rate of an SN2 reaction?

Substrate, nucleophile, good leaving group, and solvent

How does substrate influence the rate of an SN2 reaction?

-UNHINDERED substrates react the QUICKEST due to LESS crowding around electrophilic carbon

-Methyl>1>2

How do NUCLEOPHILES influence reaction rate of an SN2 mechanism?

-Strong and SMALL nucleophiles are favored; such as -OH, -CN, -NH2,

-When going DOWN the periodic table, NUCLEOPHILICITY increases (I>Br>Cl)

-Weak nucleophiles such as H20 and F not favored because too BULKY

How do good leaving groups influence SN2 rate?

Good leaving groups are NOT strong bases

How does the solvent influence SN2 reaction rate?

Aprotic polar solvent is FAVORED since solvent CANNOT strongly solvate nucleophile