OChem Exam 3-Ashton Sanchez 11/24/25 (copy)

In a ring flip for a chair conformation

axial and equatorial are switched, keeping specific bonds

1-3 Diaxial strain

Occurs on axial carbons, when bulky groups have interfering interactions with each other (bulky groups will have less strain when equatorial)

achiral

achiral is one that is superimposable on its mirror image

chiral

chiral is one that is NOT superimposable on its mirror image

optically active

pure chemical either S or R conformation

optically inactive

achiral compound or a racemic mixture

Anti addition to a E alkene

substituents will add with opposite bond types (one dashed, one wedged)

Anti addition to a Z alkene

substituents will add to the same bond type e.g. both dashed/wedged

Syn addition to a E alkene

substituents will add to the same bond type e.g. both dashed/wedged

Syn addition to a Z alkene

substituents will add with opposite bond types (one dashed, one wedged)

Strong bases are good nucleophiles

true

SN2 Reaction

bimolecular nucleophilic substitution (always a backside attack of NU compared to LG)

SN1 Reaction

unimolecular nucleophilic substitution

SN2 rxns reverse stereochemistry

true

E2 Reaction

Bimolecular elimination

E1 Reaction

unimolecular elimination

Nucleophiles

Cl-, Br-, I-, OH-, OR-, N3-,CN-, RS-

As you go down a period halogen nucleophiles become

less effective in an aprotic solvent (reversed in a protic solvent)

The more stable a nucleophile is as a base

the less effective it is

protic solvents

methanol. ethanol

1°

Sn2 only

2°

Sn2 & E2

Sn2 rxns are faster in what kind of solvent

polar aprotic

inversion of stereochemistry only at the stereocenter where rxn occurs

In E2 reactions if there is more than onee B Hydrogen to eliminate

the more substited alkene is formed, unless a bulky group is involved

Enantiomers are generated in a reaction if…

A new stereocenter is formed or an existing one is altered

protic solvent 

can act as a H bond donor

aprotic

CANNOT act as a H bond donor

ethanol

protic solvent

methanol

protic solvent

formic acid

protic solvent

H2O

protic solvent

hexane

nonpolar solvent

benzene

nonpolar solvent

diethyl ether Et2O

nonpolar solvent

chloroform

nonpolar solvent

tetrahydrofuran THF

nonpolar solvent

methylene chloride

nonpolar solvent

RO-

Strong Nucleophile and Base

OH-

Strong Nucleophile and Base

RNH2

Strong nucleophile and weak base

RS-

Strong nucleophile and weak base

N3-

Strong nucleophile and weak base

CN-

Strong nucleophile and weak base

X-

Strong nucleophile and weak base

RCO2

Strong nucleophile and weak base

CH3OH

Weak nucleophile and weak base

CH3SH

Weak nucleophile and weak base

non-nucleophilic base

non-nucleophilic base

Na+OET-

Strong base