6.1 Nucleophilic Substitution Flashcards
What is a nucleophilic substitution reaction?
replace a leaving group in an electrophilic substrate with a nucleophile
What happens to the bonds in a nucleophilic substitution reaction?
one sigma bond is broken, one sigma bond is formed
What are the typical electrophiles in an Sn2 mechanism?
alkyl halides
What are alkyl halides?
alkanes that contain at least one halogen
What is the basic overview of an Sn2 reaction?
nucleophile attacks from the backside at the same time that the leaving group leaves; occurs in a single step
What is the reaction rate dependent on in an Sn2 reaction?
concentrations of both the nucleophile and the electrophile
What solvents are best for Sn2 reactions?
polar, aprotic
What is the reactivities of substrates for Sn2 reactions?
CH3 > 1 degree»_space; 2 degree»_space;> 3 degree
What is the stereochemistry of an Sn2 reaction?
complete stereochemical inversion of the carbon that is attacked by the nucleophile
What are the favoring conditions for an Sn2 reaction?
strong, non-bulky nucleophile will favor Sn2 over Sn1
What is the basic overview of an Sn1 reaction?
leaving group falls off forming a planar carbocation with 120 bond angle and the racemization occurs as the nucleophile attacks equally on either side of the carbocation
What is the rate of the reaction dependent on for an Sn1 reaction?
concentration of the electrophile
What are the best solvents for Sn1 reactions?
protic solvents
What is the reactivity of substrate for an Sn1 reaction?
3 degree > 2 degree»_space; 1 degree
What is the stereochemistry of an Sn1 reaction?
complete racemization due to nucleophilic attack on either side of p orbital
What are the favoring conditions for an Sn1 reaction?
non-basic, weaker nucleophiles
What are alcohols treated with to make their -OH leaving group good?
mineral acids
