SQ 8: SN2, SN1, E2, , stereochem changes, rate changes, mechanism reasonability, competition

rate law for SN1 & E1 rxns

rate = k [substrate]

rate law for SN2 & E2 rxns

rate = k [substrate][nucleophile]

how to know which step is rate determining step

RDS is the step that takes more work (not super natural- ex. carbocat formation in her)

how stereochem changes for SN2 rxn

stereocenter is flipped

how stereochem changes for SN1 rxn

racemization of stereocenter (both options)

how stereochem changes for E1 rxn

makes most stable alkene (usually E stereochem alkene)

how stereochem changes for E2 rxn

anticoplanar arrangement where H and LG have to be on the same side (use Newman projections)

what happens stereochemically when an achiral molecule undergoes a rxn?

both enantiomers are made (racemic)

proton transfer mechanism reasonability rule

no proton transfers within the reaction! (instead break into 2 steps, can add add another one of the added molecules)

acidic & basic environments rule

• if in basic conditions (OH-), then cannot be an organic cat

• if in acidic conditions, then cannot be an organic anion

what 2 things contribute to competition?

1. kinetic control: which product was made faster?

2. thermodynamic control: how stable is each product?

what control only influences competition in substitution & elimination rxns?

kinetic control, so it’s all Abt rates

rate law for SN2 & E2

k [substrate] [nucleophile or base for E2]

dependent on both concentrations

SN1 and E1 rate law

k [substrate]

only depends on substrate