bromination of e-stilbene and stereochemistry

functional grp

atom or grp of atoms that governs the chemical and physical properties of a family of compoundsand participates in chemical reactions

alkenes

organic compounds possessing polarizable carbon-carbon double bond, pi bond

elimination reactions

most common ways to produce carbon-carbon pi bond

dehydration

in which C-OH single bond has elements of water removed to form alkene

dehydrohalogenation

C-X; process by which this is turned into an alkene

most common mode of addition across pi bond of alkene

involves ionic stepwise mechanism in which an electrophile attacks pi bond first (functioning as nucleophile) to produce carbocation; nuc then attacks carbocation to produce final product - electrophilic addition

markovnikovs rule

electrophile generally adds to terminus of double bond that produces more stabel carbocation

electrophilic additions are regioselective processes bc

two unsymmetrical reactants combine predominantly in one orientational sense to give on regioisomer preferentially

concerted mechanism

addition to pi bond in which each new sigma bond is formed simultaneously on same face of pi bond

addition of bromine to MANY alkenes is a _________ reaction that proceeds by ____ addition to double bond

stereospecific, anti

addition of bromine to e-stilbene is

not stereospecific bc small amts of dl-stilbene dibromide are also formed in reaction

diastereomers meso-stilbene dibromide and dl-stilbene dibromide differ in melting point by

100 degrees celsius

glassware setup for bromination

lightly capping by resting glass stopper on top of keck clip bc no pressure build up

i

if bromine spilled soak up with

sodium thiosulfate allowing brown color to slowly disappear and can be treated as halogenated organic waste

do not wash bromine-containing glassware w/

acetone

melting point of substance

temp at which the liquid and solid phases exist in equilibirium w/ one another w/o change of temp

eutectic point

equilibrium composition at which a and B melt in constant ratio in impure substance

eutectic mixture

the constant ratio at which A and B melt in equilibrium

two broad classes of stereoisomers

conformational isomers and configurational isomersc

conformational

interconverted by rotation about single bonds; generally low-energy process that occurs rapidly at room temp

configurational

interconversion requires breaking and remaking of chemical bonds, a high energy process

enantiomers also called 

optical isomers bc rotate plane of light an equal number of degrees in opposite directions