last orgo quiz.

what is a lewis acid?

electron acceptor (electron poor)

what is a lewis base?

electro donor (electron rich)

what is an electrophile?

electron poor atom that does not involve hydrogen

ACID!

what is a nucleophile?

carbon that involves electron rich atoms

BASE!

when determining nucleophilic centers, what are some things to considered with bonds?

single bonds will not be nucleophilic

lone pairs will be nucleophilic

double and triple bonds are electron rich, so they are potential nucleophilic sites

what kind of bonds are electrophilic centers?

can come from single bonds

POLAR BONDS

what four mechanistic patterns are there? (arrow-pushing patterns)

nucleophilic attack

proton transfer

loss of a leaving group

rearrangement

what are substitution reactions?

exchange an atom or group connected by one single bond

what is always involved in a substitution reaction?

loss of leaving group

two mechanisms possible for substitution reactions:

SN1 and SN2

difference between sn1 and sn2 reactions:

sn1: unimolecular, occurs in two steps

sn2: bimolecular, both steps occur at same time

how do you determine what the nucleophile vs substrate is in a reaction?

the nucleophile is the molecule that donates an electron pair to form a new bond

the substrate is the molecule containing the atom that will be substituted

so the nucleophile attacks the substrate, and replaces the leaving group on the substrate

what do sn2 mechanisms do to chirality centers?

invert them on alpha carbons

what is dmso?

dimethyl sulfoxide

promotes sn2 reactions

what is a nucleophilic attack mechanism?

a nucleophile donates a pair of electrons to an electrophilic carbon, forming a new bond

what is a proton transfer

nucleophilic attack, but involving a hydrogen

a base removes a H from an acid and adds it to itself

what is loss of a leaving group

a group breaks off, taking its bonding electrons with it

always involved in substitution reaction

what is rearrangement mechanism

a carbocation shifts to form a more stable carbocation

only happens to atoms without noble gas configuration

what kinds of rearrangement patterns are there?

hydride shift

methyl shift