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Asymmetric carbinol synthesis by means of (−)-sparteine-modified organometallic reagents
ASYMMETRIC
The reactivity
ring
OHGANOMETALLIC
H. Nozaki,
T. Aratani
and T. Toraya
of Industrial
Chemistry,
KY&o
(Received in Japan 5 June 1968;
(_),+~e& J_*_Jn,* ; a
SYNTHESIS
0F (-)-SFAHTEINE-MODIFIED
BY MEANS
Department
CARBINOL
of n-butyllithium
University,
is enhanced
by coordinating
reagents
to c&bony1
synthesis
by means
B bexane
mixture
solution
organolithium
optical
6% (3).
Ashby's
procedure
(0.5 '1) of ethylmagnesium solution
was added
2-phenylbutanoate sample
showed
obtained
The reacting
rather
solution
of ethyl
by chronatngraphy
(neat),
involved
the optical yield
are
a homogeneous
‘risted
by asymmetric
1.
solution
(-)-sparteine.
184, (5).
the
in Table
Ethyl
gel and purified
being
by
(neat),
benzene
at 5”.
benzoylformate
yield
(C.j5 t each)
up fol1owed
cc.]? +l.O"
obtaine&
on silica
car'Din&
precedent.
Work
of an equimolar
may be tentatively
of the resulting
Conformational
equivocal
of reagents
simihr’rg
in the presence
in a 5% optical
species
configuration
as indicated.
carbino1s
<2>.
and organomagnesium
in hexane
1 br.
(1:.
~~<~mm,*fri)r_
This 2-hydroxy-
by GC.
This
The same carbinol
Grignard
reaction
in (+)-2,j-
(6).
dimethoxybutane
absolute
to a benzene was isolated
without
gave l-phenyl-1-pentanol,
(4), we have prepared
bromide
(a)"," 44.4'
was previously
Other
X+~313rb~‘rs
Asymmetric
and (-)-sparteine
of benealde~?yde at -?OO during
(GC) purification
Applying
sllsaic
of organolithium
cormplex appears
of n-butyllithium
gas chromatographic yield being
addition
diamines
.&LZ.>>jB&s_*a
in the ;Dreser~ce 09 <-1-sparteine.
of a chiral
To a homogeneous was added
with the asymmetric
compounhs
Japan
tertiary
3r L,i#&*>*.&* l&gz3>* &,->*s a, .me&,,i,& ~l&$&~f_3&~,
is concerned
KY&o,
received in UK for publication 27 June 1968)
ffpprffiibg u? ~-bi~~~~rrocg-clu~~u~~ryl?s i:ezbing tu active
This paper
REAGENTS
at present
correlation
carbinols between
represented
implies
that the preferred
the inducing
in view of the lack of knowledge
and the exact mode
of attack
as shown below.
and induced
attack centres
on the detailed
The occurs is
structure
(7, 8).
* FL .I
n-Bu--Cl
R’= Me, CQOEt
4097
4098 TABLE 1 Asymmetric Induction in Carbinol Syntheaie
PhCOR'
B-IIt1
R' r C
n-BUM
n-BUM= n-BuLi'
%
20 b "D ObSd.
Yield
Product a
Concn. g/l00 ml
H
(a)-1-phenyl-1-pentanol
90
+0.26
27
+r.o
I40
(g)-2-phengl-2-hexanol
83
-0.17
22
-1.6
COOEt
(z)-ethyl 2-hgdroxy-2phenylhexanoate
85
+0.13
3.9
+6.7
to.08
1.7
t9.4
EtHgBrd
H
(I$-l-phenyl-1-propanol
15
EtHgBrd
Me
(j)-2-phenyl-2-butanol
11
< 0.01
6.5
(S)-ethyl 2-hydroxg-2phenylbutanoate
48
to.36
9.7
EtEgBre
deg.
COOEt
a All producta gave correct elemental analyses.
0
t7.4
IR and NUR spectra were
compatible with the assigned structures. b
Rotatory values were obtained in chloroform
solutions
with
5 cm cella.
The reaction was conducted ' in hexane at -7O', d in toluene at -70' or ' in benzene at 5". REFERENCES 1. A. Y. Langer. Jr., Trans. N. Y. Acad. Sci. 3,
741 (1965).
2. H. Nozaki, T. Aratani and B. Noyori, Tetrahedron Letters 2087 (1968). 3. For recorded rotations of (R)(t)-1-phenyl-1-propanol((u]z2 28.1' (neat)) and (g)())-1-phenyl-l-pentanol([u]E5 17.6O (neat)), cveeR. HacLeod, F. J. Welch and H. S. Nosher, J. Am. Chem. Sot. 8&
876 (1960).
4. E. C. Ashby and R. Reed, J. Org. Chem. 2,
971 (1966).
5. For the recorded rotation of (S)(t)-methyl 2-hydroxy-2-phenylbutanoate([a)? 24.7" (neat)), see A. McKenzie and A. Ritchie, Ber. 70, 23 (1937). -= J. Org. Chem. l8, 432 (1953). (b) N. Allentoff and
6. (a) H. L. Cohen and G. F. Wright, 0. F. Uright, J. Org. Chem. g,
1 (1957).
7. R. E. Deasg and F. Paulilc,Bull. Sot. Chim. Fr. 1373 (1963). 8. (a) E. C. Ashby, Quart. Rev. 2, J. Org. Chem- a,
259 (1967).
(b) R. 0. House and J. E. Oliver,
929 (1968).
Acknouledgement. The author6 are thankful to Prof. K. Sisido for generous help and to Dr. R. Noyori for valuable suggestions.
The reactivity
ring
OHGANOMETALLIC
H. Nozaki,
T. Aratani
and T. Toraya
of Industrial
Chemistry,
KY&o
(Received in Japan 5 June 1968;
(_),+~e& J_*_Jn,* ; a
SYNTHESIS
0F (-)-SFAHTEINE-MODIFIED
BY MEANS
Department
CARBINOL
of n-butyllithium
University,
is enhanced
by coordinating
reagents
to c&bony1
synthesis
by means
B bexane
mixture
solution
organolithium
optical
6% (3).
Ashby's
procedure
(0.5 '1) of ethylmagnesium solution
was added
2-phenylbutanoate sample
showed
obtained
The reacting
rather
solution
of ethyl
by chronatngraphy
(neat),
involved
the optical yield
are
a homogeneous
‘risted
by asymmetric
1.
solution
(-)-sparteine.
184, (5).
the
in Table
Ethyl
gel and purified
being
by
(neat),
benzene
at 5”.
benzoylformate
yield
(C.j5 t each)
up fol1owed
cc.]? +l.O"
obtaine&
on silica
car'Din&
precedent.
Work
of an equimolar
may be tentatively
of the resulting
Conformational
equivocal
of reagents
simihr’rg
in the presence
in a 5% optical
species
configuration
as indicated.
carbino1s
<2>.
and organomagnesium
in hexane
1 br.
(1:.
~~<~mm,*fri)r_
This 2-hydroxy-
by GC.
This
The same carbinol
Grignard
reaction
in (+)-2,j-
(6).
dimethoxybutane
absolute
to a benzene was isolated
without
gave l-phenyl-1-pentanol,
(4), we have prepared
bromide
(a)"," 44.4'
was previously
Other
X+~313rb~‘rs
Asymmetric
and (-)-sparteine
of benealde~?yde at -?OO during
(GC) purification
Applying
sllsaic
of organolithium
cormplex appears
of n-butyllithium
gas chromatographic yield being
addition
diamines
.&LZ.>>jB&s_*a
in the ;Dreser~ce 09 <-1-sparteine.
of a chiral
To a homogeneous was added
with the asymmetric
compounhs
Japan
tertiary
3r L,i#&*>*.&* l&gz3>* &,->*s a, .me&,,i,& ~l&$&~f_3&~,
is concerned
KY&o,
received in UK for publication 27 June 1968)
ffpprffiibg u? ~-bi~~~~rrocg-clu~~u~~ryl?s i:ezbing tu active
This paper
REAGENTS
at present
correlation
carbinols between
represented
implies
that the preferred
the inducing
in view of the lack of knowledge
and the exact mode
of attack
as shown below.
and induced
attack centres
on the detailed
The occurs is
structure
(7, 8).
* FL .I
n-Bu--Cl
R’= Me, CQOEt
4097
4098 TABLE 1 Asymmetric Induction in Carbinol Syntheaie
PhCOR'
B-IIt1
R' r C
n-BUM
n-BUM= n-BuLi'
%
20 b "D ObSd.
Yield
Product a
Concn. g/l00 ml
H
(a)-1-phenyl-1-pentanol
90
+0.26
27
+r.o
I40
(g)-2-phengl-2-hexanol
83
-0.17
22
-1.6
COOEt
(z)-ethyl 2-hgdroxy-2phenylhexanoate
85
+0.13
3.9
+6.7
to.08
1.7
t9.4
EtHgBrd
H
(I$-l-phenyl-1-propanol
15
EtHgBrd
Me
(j)-2-phenyl-2-butanol
11
< 0.01
6.5
(S)-ethyl 2-hydroxg-2phenylbutanoate
48
to.36
9.7
EtEgBre
deg.
COOEt
a All producta gave correct elemental analyses.
0
t7.4
IR and NUR spectra were
compatible with the assigned structures. b
Rotatory values were obtained in chloroform
solutions
with
5 cm cella.
The reaction was conducted ' in hexane at -7O', d in toluene at -70' or ' in benzene at 5". REFERENCES 1. A. Y. Langer. Jr., Trans. N. Y. Acad. Sci. 3,
741 (1965).
2. H. Nozaki, T. Aratani and B. Noyori, Tetrahedron Letters 2087 (1968). 3. For recorded rotations of (R)(t)-1-phenyl-1-propanol((u]z2 28.1' (neat)) and (g)())-1-phenyl-l-pentanol([u]E5 17.6O (neat)), cveeR. HacLeod, F. J. Welch and H. S. Nosher, J. Am. Chem. Sot. 8&
876 (1960).
4. E. C. Ashby and R. Reed, J. Org. Chem. 2,
971 (1966).
5. For the recorded rotation of (S)(t)-methyl 2-hydroxy-2-phenylbutanoate([a)? 24.7" (neat)), see A. McKenzie and A. Ritchie, Ber. 70, 23 (1937). -= J. Org. Chem. l8, 432 (1953). (b) N. Allentoff and
6. (a) H. L. Cohen and G. F. Wright, 0. F. Uright, J. Org. Chem. g,
1 (1957).
7. R. E. Deasg and F. Paulilc,Bull. Sot. Chim. Fr. 1373 (1963). 8. (a) E. C. Ashby, Quart. Rev. 2, J. Org. Chem- a,
259 (1967).
(b) R. 0. House and J. E. Oliver,
929 (1968).
Acknouledgement. The author6 are thankful to Prof. K. Sisido for generous help and to Dr. R. Noyori for valuable suggestions.