ochem exam 3 reagents and mechanisms

NaNH2-

strong base executing E2

KMnO4, NaOH OR OsO4, oxidant

strong oxidizing agent that adds to syn OH groups across a pi bond

Br2

anti-addition of halogen (Br or Cl) across double bond

NaOMe

strong, non-bulky base that participates in primarily E2 Zaitsev reactions with the exception of 1* alkyl halides (Sn2). in Sn2, adds OMe.

difference between NaOMe and t-BuOK

size (bulky v. small) and product (hofmann E2 vs zaitsev E2)

t-BuOK

strong, bulky base that is good at grabbing H+ ions, participates in Hofmann E2

BH3 THF, H2O2 NaOH

hydroboration-oxidation, syn addition of H and OH over a double bond through the addition of BH2 and H originally. anti-Markovnikov addition.

Br2, H2O

anti addition where OH is markovnikov, bromonium ion

H3O+, H2O

addition of OH and H across a double bond that resembles Sn1 but is electrophilic addition. Markovnikov favored.

mCPBA or CH3CO3H

epoxidation; syn-addition to an alkene from two outermost oxygens

DBU and DBN

strong bulky bases that are weak nucleophiles participating in E2 elimination

DMS

paired with O3, ozonolysis workup reagent

H3O+, H2O

alkene acid-catalyzed hydration, creates an alcohol group, markovnikov

Hg(OAC)2 H2O, NaBH4

oxymercuration demercuration; adds H and OH across a double bond following Markovnikov with no carbocation

oxymercuration vs hydroboration

one is a markovnikov alcohol, the other is an antimarkovnikov alcohol

H2, Lindlars catalyst

hydrogenation of an alkyne that becomes an alkene, sys addition

9-BBN or R2BH H2O2 NaOH

alkyne hydration with anti-markovnikov, enol-ketone tautomerization, add double bonded oxygen with H on the end

O3

ozonolysis; addition of 3 oxygens over a double bond

OsO4, NMO

syn-dihydroxylation, adding two OH over a double bond

NaCN

good nucleophile, participate in Sn reaction to replace leaving group with CN

DMSO

polar protic solvent for Sn2

KOtBu

strong hindered base participating in E2 reactions

Na, NH3 (l)

trans and anti-addition of H to form alkene from alkyne, requires radicals from Na

H2SO4, H2O HgSO4

markovnikov addition of OH to form an enol group that is tautomerized into ketone

difference between H2SO4 HgSO4 and R2BH

HgSO4 is markovnikov, R2BH is antimarkovnikov

NaNH2 Et—I

removal of terminal H to add Et or whatever group I is bonded to

X2 CCl4

halogenation of alkynes into alkene or alkane. alkene favors trans. must have excess X to convert to alkane, where there are 2 X added to 1 C

difference between H2 lindlars cat and Na NH3

one yields cis H placement and the other yields trans H placement

difference between mCPBA and OsO4

anti addition of OH vs syn addition of OH

ROOR

works with compounds to provide anti-markovnikov effect

H2 Pt

hydrogenation of alkynes that can proceed them to alkanes, addition is syn (creates stereoisomer)