Species
Protecting Group (PG) or
Reagent (R)
Use(s)
Notes
acetate
PG
Ester PG
removed with OH-
benzoate
pivalate
PG
PG
Ester PG
Ester PG
removed with OHreact with 1° alcohol selectively
TMS (trimethyl silyl ether)
TBS (TBDMS, tert-butyl dimethyl
silyl ether)
TBDPS (tert-butyl diphenyl silyl
ether)
PG
Silyl Ether PG
PG
Silyl Ether PG
PG
Bn (benzyl ether)
PMB (para-methoxy benzyl ether)
PG
PG
Tr (triphenyl methyl or trityl ether)
Boc (t-butyloxycarbonyl)
PG
PG
Silyl Ether PG
Benzyl Ether
PG/Amine PG
Benzyl Ether PG
Benzyl Ether
PG/Amine PG
Carbamate PG
removed by acid, F- ion, or MeOH/NaHCO3
removed by (AcOH, H2O,THF) or F- ion;
preferential to 1° alcohol
only removed by F- ion;
even more preferential to 1° alcohol
Cbz (carboxybenzylcarbonyl)
Fmoc (fluorenylmethyloxycarbonyl)
PG
PG
Carbamate PG
Carbamate PG
Ts (para-toluenesulfonyl)
PG
Sulfonamide PG
removed with H2/Pd-C
removed with amine base (either morpholine or piperidine)
add with 2 equivalents of Ts-Cl;
removed with Na, naphthalene
Ns (para-nitrophenylsulfonyl)
PG
Sulfonamide PG
removed with PhSH/K2CO3
NaBH4
R
reducing agent
will reduce aldehydes and ketones, but not esters
LiBH4
R
will reduce esters
LiAlH4
R
reducing agent
stronger reducing
agent
will reduce aldehydes, ketones, and esters
pyridine (C5H5N)
R
base/solvent
collect H+ ions formed during reaction
Et3N (triethylamine)
R-MgX
THF (tetrahydrofuran)
R
R
R
base
Grignard Reagent
solvent
collect H+ ions formed during reaction
R= alkyl, allyl, or aryl group; X=halide
CH2Cl2
DMF (dimethylformamide)
R
R
solvent
solvent
removed with DDQ
removed with TFA
removed with TFA
Imidazole (C3H4N2)
R
base
produces mildly basic solution
TBAF (n-Bu4NF)
Fluoride ion
R
R
salt
salt
TBS-halide
R
salt
TBDPS-halide
NaH
Ph-Br (Bn-Br, benzyl bromide)
PMB-Cl
Tr-Cl
R
R
R
R
R
salt
salt
salt
salt
salt
H2/Pd-C
R
hydrogen source
H2/Pd(OH)2-C (Pearlman's Catalyst)
TFA (trifluoroacetic acid)
DDQ (dichloro-dicyanobenzoquinone)
chloromethyl ether
R
R
hydrogen source
acid
provide F- ions
removes all silyl ether PG
adds TBS PG;
also is a Lewis Acid (provides H+ ions)
adds TMS PG;
also is a Lewis Acid (provides H+ ions)
adds TBDPS PG;
also is a Lewis Acid (provides H+ ions)
deprotonates alcohols
adds Bn PG
adds PMB PG
adds trityl PG
saturates multiple bond;
removes benzyl ether PG or Cbz PG
saturates multiple bond;
removes benzyl ether PG or Cbz PG
removes trityl PG or Boc PG
R
R
oxidant
HOCH2CH2OH (ethylene glycol)
R
used to create carbonyl acetal PG
TMSOCH2CH2OTMS
R
used to create carbonyl acetal PG
NaIO4
TBSOTf
R
R
salt
salt
cleaves a 1,2 diol into an aldehyde and ketone
adds TBS to 2° alcohol!
2,6-lutidine
R
base
collect H+ ions formed during reaction
Ph3P/Halogen
R
Appel Reaction
(MeO)2CMe2
PCC (pyridinium chlorochromate)
R
R
carbocation creator
milder oxidizing agent
will replace alcohol group with halide group
creates acetonide (carbocations latch onto neighboring
alcohol groups)
oxidizes 1° alcohol to aldehyde
TsOH (para-toluenesulfonic acid)
R
acid
Ph3P=CH©
R
Wittig Reaction
TMS-halide
removes only PMB PG
used to create ether acetal PG
provides H+ ions for reaction
turns carbonyl group into alkene and adds group
represented by ©