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A new method for converting alkyl halides to homologous aldehydes
0040-40j9/60/0422-1677$02.00/O
Tetrahedron Letters Vol. 21, pp 1677 - 1680 @Pergamon Press Ltd. 1980. Printed m Great Britain
A
NEW
METHOD
FOR
CONVERTING
ALKYL
HALIDES
TO
HOMOLOGOUS
ALDEHYDES
by
DAVID
J.
Department +
Present
AND
of Chemistry,
Address
Chemistry,
The
Lrverpool
Summary product
AGER+
C.
The University, Robert
Robinson
University,
Laboratories,
P.O.
Box 147,
suffer
continumg
search
the problem
for alternatives,
thiotrrmethylsilylmethane has been used to prepare Carey4 with
noted
methyl
In good yield
vinyl
if hexane
2)
use in organrc
3BX.
and the
synthesis.
to hydrolyse*.
They
do,
In the
the use of phenyl-
derivative
of the lithium
We have found
that
of (1)
is known3
derrvatrve
and
was not very
the alkylation
Instead
is used as the solvent,
1) “BuLi/Et20
L69
sulphides3r4t5.
tj,N,N’,N’-tetmmethylethylenedtamine -PhSMe
of Organic
and rearmngement.
difficult
I tthrum
that alkylatmn
Iodide.
Department
we have investigated The
(1).
wide
of berng
5NH
can be alkylated
by oxidation
have found
from
SO9
Liverpool
lithrum
to the aldehydes
1,3-Dithians’t* however,
COOKSON
Southhampton
Phenylthiotrimethylsilylmethyl hydrolysed
except
RICHARD
good
can be carried
of THF,
in the presence
>
1) “BuLi/TMEDA
PhSCHZSiMe3
Me&Cl
2)
Phenylthiotrimethylsrlylmethane by treating 18h.
thioanlsole
with
and quenching
of
(TMEDA).
RX
>
PhSCHRSiMea
hexane
(1)
for
out
(2) (1)
n-butyllithlum
the resulting
IS
easily
prepared
In hexane-ether,
suspension
in high yield
heating
of the llthlum
under
derrvatrve
(95%)
reflux
with
chlorotrimethylsilane6. The Note hexyl
bromrde.
results
of the olkylatron
that olkylatron
occurred
experrments with
are given
set-butyl -
in table
bromrde
1.
but not with
cyclo-
1678
Table
1.
1)“BuLi/TMEDA/hexane/O°C
PhSCH+Mq
2)
(1)
PhSCHRSiMe3
Rx
(2)
Yield
Rx
of alkylated
Mel
99
Etl
90
“PrBr
82
CH2=CHCH2Br
85
“BuBr
84
*BuBr
45
nCEiH,,Br
82
“GH,,t
86
nCaH,3 Br
81
nC, ZHzsBr
78
PhCHlBr
83
All
new compounds
The alkylated (MCPBA) reflux
(2)a
0
=CaH,,Br
a
product
have been fully
compounds
rn dichloromethane
in benzene
been proposed
could
be converted
in turn
oxidrsed
at -23’C.
for 4h to give
have already
were
chamcterised.
with
_m-chloroperoxybenzoic
The sulphoxidewere
then
heated
the 0-trimethylsilyl-S-phenylthioacetals
as a method
of protecting
to the aldehyde
by treatment
carbonyl with
acid under ‘t*
compounds’, dilute
whrch and
hydrochloric
acid. The table
2.
results
of the oxidatron
and rearrangement
experrments
are given
in
1679
Table
2. +
MCPBA >
PhSCHRSiMes
4
PhS(O)CHRSiMej
CH$&/-23°C
Yields (2),
Sulphoxtdea
R=
PhSCHROSiMes
.=+
(%) AcetaIa
Aldehydeb d
H
91
89’
Me
83
97
Et
89
88
“Pr
92
85
CH2=CHCH2-
90
81
“Bu
92
83
72a’=
‘Bu
92
83
74ate
“GH,,
88
82
68aRe
“C4Ht3
91
85
77a,e
“‘&Hz
96
88
80a
(71f)
PhCH2
96
92
85’
(77f)
a.
Yteld
b.
Overall
c.
The reormngement for
by n.m.r. yield. wos carried
out by heating
Denotes
the acetal
e.
isolated
OS 2,4_dinitrophenylhydrozone.
f.
Isolated
yield.
In a typical was added to a stirred lml,
1Ommol)
experrment
in carbon
at Oy,
of the n-butyll
under
chloride
distilliation
to gave after
phenylthiotrimethylsilylmethone
suspension
The
reaction
was slowly
added too
dichloromethane with
sotututed
cooled (20ml)
After
was worked
acid (dry
under
aqueous
nitrogen3.
rthium
(1 .OSmmol)
Ice-carbon nttrogen.
sodium
lh,
up with
or chromatogrrrphy
_m-Chloroperoxybenzorc
woshed
reflux
tetmchloride
was not hydrolysed.
wos added dropwtse.
in
under
3h.
d.
(15.
RCHO
(1Ommol
hydrogen
1Ommol)
in hexane)
the alkyl
halide
saturated
aqueous
the alkyloted
- TMEDA
(1Ommol) ammonium
compound
In dry dichloromethane
tetrachloride) After
(1.969,
solutron
betng sttrred
carbonate
for
and water,
2h,
of
(2).
(30ml) (2)
(1 .Ommol)
the mtxture dried,
wos
1680
evaporated
in vacua
borled
under
to that
prepared
nitrogen
The (1)
with
an oil
reactions
electrophiles
in dry benzene
(10ml)
derivative
identical
of phenylthiotrimethylsilylmethane
as epoxrdes
be the subtect
Postdoctoral
and unsatumted
of future
Fellowshrp
(to
ketones)
and the
papers.
D.J.A.)
is gratefully
acknowledged,
REFERENCES 1.
D.
Seebach,
2.
8.
-T.
3.
D. J.
Peterson,
4.
F.A.
Carey
and 0.
5.
F.A.
Carey
and A. S.
6.
H.
7.
Gtlman
A.G.
8.
E.
9.
T.H.
(Received
Synthesis,
Grobel
J.
Hernandez,
UK
Court, Webb,
Ong,
77 February
J. J.
Synthesis,
1977,
1968,
780
J.
33,
Org.
Chem.,
Org.
Chem.,
Amer.
Chem.
Anderson,
Mullins,
Chan and B.S.
m
Chem.,
and D. G.
and M.
17
Seebach,
Org.
and F. J.
Brock
Vedejs
1969,
and D.
and
of Ghan’.
(such
will
was dissolved
the E)-trrmethylsrlylphenylthloacetal
of the lithium
of ketones An S.R.C.
which
for 4h to give
by the method
other
prepamtion
to give
1973,38, 1972,
Sot.,
37, 1940,
J.
Chem.,
Tetrahedron
Lett.,
1975,
2017
Tetmhedron
Lett.,
1976,
319
1980)
Canad.
357
2670 939 62,
1968,46,
98 2115
Tetrahedron Letters Vol. 21, pp 1677 - 1680 @Pergamon Press Ltd. 1980. Printed m Great Britain
A
NEW
METHOD
FOR
CONVERTING
ALKYL
HALIDES
TO
HOMOLOGOUS
ALDEHYDES
by
DAVID
J.
Department +
Present
AND
of Chemistry,
Address
Chemistry,
The
Lrverpool
Summary product
AGER+
C.
The University, Robert
Robinson
University,
Laboratories,
P.O.
Box 147,
suffer
continumg
search
the problem
for alternatives,
thiotrrmethylsilylmethane has been used to prepare Carey4 with
noted
methyl
In good yield
vinyl
if hexane
2)
use in organrc
3BX.
and the
synthesis.
to hydrolyse*.
They
do,
In the
the use of phenyl-
derivative
of the lithium
We have found
that
of (1)
is known3
derrvatrve
and
was not very
the alkylation
Instead
is used as the solvent,
1) “BuLi/Et20
L69
sulphides3r4t5.
tj,N,N’,N’-tetmmethylethylenedtamine -PhSMe
of Organic
and rearmngement.
difficult
I tthrum
that alkylatmn
Iodide.
Department
we have investigated The
(1).
wide
of berng
5NH
can be alkylated
by oxidation
have found
from
SO9
Liverpool
lithrum
to the aldehydes
1,3-Dithians’t* however,
COOKSON
Southhampton
Phenylthiotrimethylsilylmethyl hydrolysed
except
RICHARD
good
can be carried
of THF,
in the presence
>
1) “BuLi/TMEDA
PhSCHZSiMe3
Me&Cl
2)
Phenylthiotrimethylsrlylmethane by treating 18h.
thioanlsole
with
and quenching
of
(TMEDA).
RX
>
PhSCHRSiMea
hexane
(1)
for
out
(2) (1)
n-butyllithlum
the resulting
IS
easily
prepared
In hexane-ether,
suspension
in high yield
heating
of the llthlum
under
derrvatrve
(95%)
reflux
with
chlorotrimethylsilane6. The Note hexyl
bromrde.
results
of the olkylatron
that olkylatron
occurred
experrments with
are given
set-butyl -
in table
bromrde
1.
but not with
cyclo-
1678
Table
1.
1)“BuLi/TMEDA/hexane/O°C
PhSCH+Mq
2)
(1)
PhSCHRSiMe3
Rx
(2)
Yield
Rx
of alkylated
Mel
99
Etl
90
“PrBr
82
CH2=CHCH2Br
85
“BuBr
84
*BuBr
45
nCEiH,,Br
82
“GH,,t
86
nCaH,3 Br
81
nC, ZHzsBr
78
PhCHlBr
83
All
new compounds
The alkylated (MCPBA) reflux
(2)a
0
=CaH,,Br
a
product
have been fully
compounds
rn dichloromethane
in benzene
been proposed
could
be converted
in turn
oxidrsed
at -23’C.
for 4h to give
have already
were
chamcterised.
with
_m-chloroperoxybenzoic
The sulphoxidewere
then
heated
the 0-trimethylsilyl-S-phenylthioacetals
as a method
of protecting
to the aldehyde
by treatment
carbonyl with
acid under ‘t*
compounds’, dilute
whrch and
hydrochloric
acid. The table
2.
results
of the oxidatron
and rearrangement
experrments
are given
in
1679
Table
2. +
MCPBA >
PhSCHRSiMes
4
PhS(O)CHRSiMej
CH$&/-23°C
Yields (2),
Sulphoxtdea
R=
PhSCHROSiMes
.=+
(%) AcetaIa
Aldehydeb d
H
91
89’
Me
83
97
Et
89
88
“Pr
92
85
CH2=CHCH2-
90
81
“Bu
92
83
72a’=
‘Bu
92
83
74ate
“GH,,
88
82
68aRe
“C4Ht3
91
85
77a,e
“‘&Hz
96
88
80a
(71f)
PhCH2
96
92
85’
(77f)
a.
Yteld
b.
Overall
c.
The reormngement for
by n.m.r. yield. wos carried
out by heating
Denotes
the acetal
e.
isolated
OS 2,4_dinitrophenylhydrozone.
f.
Isolated
yield.
In a typical was added to a stirred lml,
1Ommol)
experrment
in carbon
at Oy,
of the n-butyll
under
chloride
distilliation
to gave after
phenylthiotrimethylsilylmethone
suspension
The
reaction
was slowly
added too
dichloromethane with
sotututed
cooled (20ml)
After
was worked
acid (dry
under
aqueous
nitrogen3.
rthium
(1 .OSmmol)
Ice-carbon nttrogen.
sodium
lh,
up with
or chromatogrrrphy
_m-Chloroperoxybenzorc
woshed
reflux
tetmchloride
was not hydrolysed.
wos added dropwtse.
in
under
3h.
d.
(15.
RCHO
(1Ommol
hydrogen
1Ommol)
in hexane)
the alkyl
halide
saturated
aqueous
the alkyloted
- TMEDA
(1Ommol) ammonium
compound
In dry dichloromethane
tetrachloride) After
(1.969,
solutron
betng sttrred
carbonate
for
and water,
2h,
of
(2).
(30ml) (2)
(1 .Ommol)
the mtxture dried,
wos
1680
evaporated
in vacua
borled
under
to that
prepared
nitrogen
The (1)
with
an oil
reactions
electrophiles
in dry benzene
(10ml)
derivative
identical
of phenylthiotrimethylsilylmethane
as epoxrdes
be the subtect
Postdoctoral
and unsatumted
of future
Fellowshrp
(to
ketones)
and the
papers.
D.J.A.)
is gratefully
acknowledged,
REFERENCES 1.
D.
Seebach,
2.
8.
-T.
3.
D. J.
Peterson,
4.
F.A.
Carey
and 0.
5.
F.A.
Carey
and A. S.
6.
H.
7.
Gtlman
A.G.
8.
E.
9.
T.H.
(Received
Synthesis,
Grobel
J.
Hernandez,
UK
Court, Webb,
Ong,
77 February
J. J.
Synthesis,
1977,
1968,
780
J.
33,
Org.
Chem.,
Org.
Chem.,
Amer.
Chem.
Anderson,
Mullins,
Chan and B.S.
m
Chem.,
and D. G.
and M.
17
Seebach,
Org.
and F. J.
Brock
Vedejs
1969,
and D.
and
of Ghan’.
(such
will
was dissolved
the E)-trrmethylsrlylphenylthloacetal
of the lithium
of ketones An S.R.C.
which
for 4h to give
by the method
other
prepamtion
to give
1973,38, 1972,
Sot.,
37, 1940,
J.
Chem.,
Tetrahedron
Lett.,
1975,
2017
Tetmhedron
Lett.,
1976,
319
1980)
Canad.
357
2670 939 62,
1968,46,
98 2115