Exam 3 - Organic Chemistry Reaction Mechanisms

syn addition

the added substituents end up on the same side of the former double bond so both are on dashes or both are on wedges

anti addition

addition refers to the addition of substituents on opposite sides of a double bond, where one is on a dash and the other is on a wedge.

anti-Markovnikov addition

substituent bonds to the less substituted carbon

Markovnikov addition

substituent bonds to the more substituted carbon in an alkene reaction.

hydroboration-oxidation mechanism (BH3*THF)

products: OH

anti-Markovnikov addition, syn addition

catalytic hydrogenation (H2, Pd/C)

adds identical H atoms in syn addition

halogenation (Br2, Cl2/CH2Cl2)

adds identical halogens from the reagent in anti addition (one wedge, one dash)

halohydrin (Br2, Cl2/ H2O)

anti-Markovnikov addition of one halogen and OH

halogen and OH add in anti conformation (one on dash, one on wedge)

oxymercuration-demercuration (Hg(OAc)2, H2O)

products: OH

Markovnikov addition, added in both syn and anti arrangements
show both arrangements because stereochemistry is non specific

oxymercuration (first step in oxymercuration-demercuration, forms an intermediate)

anti addition
OH bonds in Markovnikov addition
Hg(OAc) bonds in anti-Markovnikov addition

demercuration (second step in oxymercuration-demercuration)

no specificity in arrangements

hydrohalogenation (HBr, HCl)

products: halogen
Markovnikov addition, added in both syn and anti arrangements
stereochemistry is nonspecific, so show both arrangements

most stable chair conformation

largest substituent groups in equatorial position

least stable chair conformation

half chair (leftmost carbon is raised so that it shares the same plane as the other 2 carbons bonded to it)