Reactions Alco Al co ho l React Reactio io ns
Dehydration
R
H2SO4 R
R''
(watch (watch for carbocati carbocation on rearrange rearrangem ments) ents)
R'
R'' OR
boxed boxed means eans you will will not not be respo responsi nsibl ble e for knowing knowing the the mechanism echanism
R' OH POCl3, pyrid pyridine ine
R
R''
R' Making Ma king alkyl halides
H-X, H-X, Et2O
R OH R OH
PBr3, Et2O SOCl2, pyrid pyridine ine
R OH
R X
(usu (usual ally ly 3° alco alcoh hols) ols) X =I, Br, Br, Cl
R Br
(for (for 1° or 2 alco alcoh hols) ols)
R Cl
(for (for 1° or 2 alco alcoh hols) ols)
TsCl, TsCl, pyridin idine e R OH
(tosyl (tosylat ates es behav behave e like like halide halides) s)
R OTs
Alco Al co ho l Oxi Oxidat dat io n
PCC, PCC, CH2Cl2 (1 )
R
R
OH CrO3 H2SO4, H2O
R
OH
(2 )
R
OH
R'' (3 )
R' R
OH
water ater mustbe ust be absen absentt to stop stop att at the alde aldehy hyde de stag stage e
OH R
CrO3 H2SO4, H2O
R'
O
OR
K 2Cr2O7 H2SO4, H2O
OR
K 2Cr2O7 H2SO4, H2O
O R'
R
O
Not Oxid Oxidize ized d by these hese Cr reag reagen entts
OR
PCC
Ethers Ether Formation
1. NaH 2. R'-X R OH
R
Ether Reactions
R
O R'
Williamson ether synthesis
(Usually unreactive)
H-X
O
(subjectto the usual considerations for SN2 reactions)
R X
R'
+
(X =Cl, Br, I)
X R'
Epoxides Epoxide Formation - fromalkenes (see below) Epoxide Reactions
With strong nucleophiles (basic conditions): O
OH
Nuc
R
Nuc
R
Nuc
=
OR,
R, etc
attack at the less hindered position (S N2 like)
Under acidic conditions: O
Nuc
H , NucH
R
OH
R
NucH
=
H-X, H2O, ROH
attack at the MORE hindered position (SN1 like), inversion of configuration (SN2 like)
Alken e For matio n
R
R''
H2SO4
R' OH R R' X
R
R'' dehydration
R' R''
KOH, EtOH
R R'
R''