stereochem & bromination

what happens to esters in a cis orientation?

the esters are close to one another in space, electrons that make up the lone pairs and bonds in the esters repel one another

two broad classifications of stereoisomers that are of importance in organic chemistry 

conformational and configurational

1,2-cyclohexanediol

cis-1,2-cyclohexanediol

trans-1,2-cyclohexanediol

trans-1,2-cyclohexanediol

dimethyl maleate

dimethyl fumarate

cis-1,4-dimethylcyclohexane

trans-1,4-dimethylcyclohexane

example of geometric isomers

dimethyl maleate & dimethyl fumarate

dimethyl maleate

dimethyl fumarte

what to clean bromine with

sodium thiosulfate

do not wash glassware that contained bromine with_

acetone

bromine carciogenicity

not a know carcinogen

bromine mutagenicity

not a known mutagen

dochloromethane carciogenicity

known carcinogen

dochloromethane mutagenicity

possible mutagen

d,l-stilbene dibromide carciogenicity

not a known carcinogen

(E)-stilebene carciogenicity

not a known carcinogen

(E)-stilebene mutagenicity

possible mutagen

meso-Stilbene dibromide carcinogenicity

not a known carcinogen

cyclohexene mutagenicity

not a known mutagen

cyclohexene carcinogenicity

not a known carcinogen

dimethyl fumarate carcinogenicity

not a known carcinogen

dimethyl fumarate mutagenicity

not a known mutagen

dimethyl maleate carcinogenicity

not a known carcinogen

dimethyl maleate mutagenicity

not a known mutagen

ethanol carcinogenicity

not a known carcinogen

ethanol mutagenicity

possible mutagen

what are the two extremes for an even distribution

1:1:1, 1:0:0

the results will be mostly ___

meso

what can explain why it is mostly meso

there is a mixture of cations in solution and if the cyclic cation is favored this can explain why we are getting mostly meso

enantiomers

non-superimposable, mirror images, almost identical

diasteriomers

not superimposible, non-mirror image, different properties

energy for single c-c bond

83

energy for a double c-c bond

146

what energy do we need?

either the full single bond or the difference between the two (70-80)

what is the source of energy in the lab?

lab

energy needed to break c-c in this lab

right at the end of the visible spectrum and lightly moving into UV spectrum

energy much to break br-br

46

light for br is __ nm; which is __ on the visible spectrum

600; in the middle

what can we assume about the breaking of bonds in this lab?

because light has a role we can guess homolytic cleavage

major assumption with radicals

unstable/reactive due to unpaired electrons

how do we minimize pressure?

lightly resting stopper in round-bottom flask and balanced in the Keck Clamp

color change throughout lab

orange color disappears and solution becomes colorless

bromination of alkene is a ___ rxn

oxidation

Markovnikov’s Rule

hydrogen atom in an electrophilic addition reaction to an alkene adds to the cation of the double bond that already has more hydrogen atoms, resulting in the halide attaching to the more substituted carbon

cyclic cation results in__

100% meso

intermediate cation results in ___

50/50 L/D and meso

when to stop bromination rxn

after 10-15 min or until most of the orange color disappears and a white solid has formed

how much cyclohexane to add

one drop

eutectic point

substance A and B melt at constant ration

cis-trans isomers are ___ isomers

geometric

stereocenter of l isomer

1R,2R

stereocenter of d isomer

1S, 2S

racemate quality

will not rotate plane polarized light

meso compound characteristics

optically inactive and achiral. they have two or more stereocenters and a superimposable mirror image

dimethyl fumarate is a _ at room temp

solid

dimethyl maleate is a _ at room temp

liquid

cyclohexan and br rxn

cyclohexane reacts with Br to create a dibromide which serves to destory residual bromide

alkenes

organic compounds with a polarizable c-c double bond

most common way to produce c-c doubl ebond

elimination rxn

functional group of alkyl halide

carbon halogen single bond

dehydrohalogenation

carbon-hydrogen bond converted to carbon-carbon pi bond

dehydration

double bond formed by removing elements of water from alcohol

adding a reagent across a double bond is __

exothermic

most common mode of addition reaction

ionic stepwise mechanism where E+ first attacks the pi-bond and the nucleophile attacks the carbocation aka electrophilic addition

concerted mechanism

each new sigma bond is formed simultaneously on the same face of the pi bond

bromine fire hazard

negligible

bromine inhalation

irritation, mucous secretion, coughing, nosebleed, headache, delayed nausea, diarrhea & abdominal pains, pulmonary edema, pneumonia

bromine skin contact

cooling/burning sensation, redness, pain, discoloration, blisters, pustules, burns, ulcers

bromine eye contact

redness, pain, blurred vision, loss of vision, lacrimation, photophobia

bromine ingestion

burns of mouth, throat, stomach, brown discoloration/corrosion of tongue and mucous membrane, sore throat and vomiting

cyclohexane fire hazard

severe fire hazard

cyclohexane inhalation

irritation, cns depression, headache, dizziness, drowsiness, labored breathing, kidney/liver damage

cyclohexane skin contct

defatting, redness, burning

cyclohexane eye contact

redness and irritation

cyclohexane ingestion

nausea, labored breathing, cns involvement, aspiration, pneumonia

dichloromethane fire hazard

slight fire hazard

dichloromethane inhalation

irritation, lightheadedness, dizziness, tingling, numb extremes, heat, full head, confusion, nausea, headache, fatigue

dichloromethane skin

irritation, possible burns, skin absorption may cause inhalation-like effects

dichloromethane eye contact

pain and extreme irritation

dichloromethane ingestion

rapid then slowed respiration, GI ulceration and hemorrhage, unconsciousness, cns depression, liver/kidney damage

dimethyl fumarate fire hazard

slight fire hazard

dimethyl fumarate inhalation

irritation, coughing, dryness

dimethyl fumarate skin contact

irritation and redness

dimethyl fumarate eye contact

irritation

dimethyl fumarate ingestion

relatively non-toxic, large amounts may cause sore throat, vomiting, abdominal pain

dimethyl maleate fire hazard

moderate fire hazard

dimethyl maleate inhalation

irritation, coughing, dyspnea

dimethyl maleate skin contact

irritation, redness, pain

dimethyl maleate eye contact

irritation, redness, pain, corneal erosion

dimethyl maleate ingestion

sore throat, abdominal pain, vomting

ethanol fire hazard

severe fire hazard

ethanol inhalation

irritation, cns depression with headache, stupor, fatigue, dizziness, drowsiness, dullness, lassitude, loss of appetite

ethanol skin contact

redness, burning, contact dermatitis, possible skiin absorption

ethanol eye contact

immediate burning, stinging, reflex closure of lids, tearing, and temporary injury of corneal epithelium

ethanol ingestion

emotional lability, decreased inhibitions, exhiliration, boastfulness, beligerance, visual impairment, muscular incoordination, sensory disturbances, dilated pupuls, rapid pulse, nausea, vomiting, sweating, drowsiness, stupor