close

Вход

Забыли?

вход по аккаунту

?

Enantioselective Synthesis of Homoallyl Alcohols via Chiral Allylboronic Esters.

код для вставкиСкачать
[5] C . M o n a in G. Chiurdoglu: Conformational Analysis. Academic Press.
New York 1971.
161 6('H)=0.39 (t, C51, C52), 0.42 (d, C12, C22, C32, C42), and 0.46 (d,
C11, C21, C31, '241); S("C)=-2.1 (t), -4.7 (d), and -5.1 (d); both
spectra rel. TMS, CD2Cl2-soln.,2.1 14T.
[7] Method 1: tetrahedral extension on phosphorus atom; method 2: connecting line between the mass center of the triangle (Sn2Sn5Sn3) and
PI ; both methods afford the same numerical results.
(Z)-SDecenyl Acetate, a Sex Attractant for the Male
Turnip Moth Agvotis segeturn (Lepidoptera)[**l
By Hans Jiirgen Bestmann, Otto Vostrowsky, Karl-Heinz
Koschatzky, Hans Platz, Thorolf Brosche, Iwan Kantardjiew,
Marties Rheinwald, and Werner Knauf "1
The turnip moth Agrotis (=Scotiu) segetum (Noctuidae,
Lepidoptera) is an ubiquitous grain pest, which up to the
present time has proved very difficult to control. An electroantennogram screening (EAG screening)"' with ca. 100 unsaturated aldehydes, alcohols, and their acetates on the antennas
of the male species of the insects showed that (Z)-5-decenyl
acetate (7) caused the greatest excitation. We still found
EAG responses on loading the stimulus source with as
little as 10- pg of (7). As expectedi2,31 (Z)-7-dodecenyl acetate
also exhibits high EAG activity.
We have synthesized (7) according to Scheme 1.
CHo(CHdsCH0
(3)
*
H $
CH,(CH,),~=C(CH,),CH=CH,
B=C:H( C H ),~C H C~H ~ O H
CH, (CH, ) 3~
I ) 9-BBN
(5)
I
2) HzOz/NaOH
14)
polarity (pentane/diethyl ether/methanol) into 17 fractions, the
physiological activity of which was determined by means of
the EAG test. The active fractions were combined, concentrated in a stream of nitrogen and analyzed by capillary gas
chromatography synchronously with a flame ionization detector and EAG dete~tor'~!
The EAG detector showed a physiologically active compound having the retention time of (Z)-5decenyl acetate (7). Cochromatography of synthetic (7) gave
retention times identical with those of the contents of the
gland substances.
Proof of the presence of (7) in the sex glands of the females
was provided by an analysis of the extract by coupled capillary
gas chromatography-mass
spectroscopy. 17 ionsi6] were
inferred from the mass spectrum of synthetic (7). All these
ions could be determined simultaneously in the chromatogram
of the extract, precisely at the previously determined retention
time of (7). For further proof of the structure, the pheromone
extract was separated gas chromatographically on a packed
column; fractions were collected at minute intervals in cooled
glass capillaries. Once again, according to the EAG test the
activity was found in the fraction having the retention time
of synthetic (7).
Synthetic (Z)-S-decenyl acetate (7) was transferred to
a multistep single-tube olfactometeri71, monitored with an
automatic television camera fitted with time scanning and
magnetic tape printout, and its efficacy as an attractant for
male turnip moths was checked. (7) proved to have a luring
effect up to attractant loadings of 10-6kg, whereas above
pg an inhibiting effect was observed.
Trapping of the male species in open wind-socks was
still recorded at a loading of 5 x 10-4c(g of (7); more than
0.5 pg of (7) has an inhibiting effect.
Thus, (Z)-5-decenyl acetate (7) has been identified for the
first time as a sex attractant for Lepidoptera. It is more effective
than any of the previously reported butterfly pheromone components.
AczOIPy
Received: July 26, 1978 [Z 63 IE]
German version: Angew. Chern. 90, 815 (1978)
CAS Registry numbers:
( I ) , 56771-29-0; ( 2 ) , 67773-68-6; ( 3 ) , 110-62-3; ( 4 ) , 67773-69-7; ( 5 ) . 280-648; (ti), 51652-47-2; (7), 67446-07-5
The phosphonium salt (1 ), obtainable from 4-pentenyl bromide and triphenylphosphane, is converted by the silazide
methodr4I into the ylide (2), which reacts with pentanal (3)
at - 78 "C in a (Z)-stereoselective Wittig reaction to give l,(Z)5-decadiene ( 4 ) , b. p. 55-57"C/14 torr, yield 62"/,. Hydroboration of ( 4 ) with 9-borabicyclo[3.3.1]nonane (5) (9-BBN)
and subsequent oxidation with H 2 0 2affords the alcohol ( 6 ) ,
b.p. 114-115"C/14 torr, yield 82%, which on acetylation
gives the acetate (7), b.p. 105-107"C/16torr, yield 87%.
In order to identify the natural pheromone the abdominal
tips with sex glands were excised from 500 females and together
extracted with hexane. The pheromone extract was filtered
and separated chromatographically on a silica gel column
(0.06-0.2 mm, 30 x 1.5cm) with an eluent system of increasing
[*I Prof. Dr. H. J . Bestmann, Dr. 0. Vostrowsky, Dipl.-Chern. K.-H.
Koschatzky, DipLChem. H. Platz, Dipl.-Chem. T. Brosche, Dr. I.
Kantardjiew, M. Rheinwald
Institut fur Organische Chemie der Universitat Erlangen-Nurnberg
Henkestrasse 42, D-8520 Erlangen (Germany)
Dr. W. Knauf
Hoechst AG, D-6230 Frankfurt/M.-Hochst (Germany)
[**I Pheromones, Part 22.-Parts 20 and 21 : H . J . Bestmann, J . Suss, 0
Vostrowsky, Tetrahedron Lett. 1978, in press.
768
[I] D. Schneider, Z. Vgl. Physiol. 4 0 , 8 (1957).
[2] 0.Vostrowsky, H . J . Bestmann, E. Priesner, Nachr. Chem. Tech. 21,
501 (1973).
131 E. Priesner, M . Jacobson, H . J . Bestmann, Z. Naturforsch. C30, 283
(1975).
[4] H . J . Bestmann, W Stransky, 0 . Vostrowsky, Chem. Ber. 109, 1694 (1976).
[ S ] H . A m , E . Stadler, S. Rauscher, Z . Naturforsch. C30, 722 (1975).
96 (C7H 121,
161 mle = 138 ( C d 1 a), 137 (CIOHI 7), 1 10 (C&id. 109 (CsH d,
95 ( C ~ H I I 94
) , (C7Hio), 93 (C7H91,81 (c6H9), 80 (C~HS),79 (C6H71,
73 (CHzOCOCH,), 67 (CjH,), 66 (CjH6), 65 (CsHj), 61 (CHpCOOH*),
and 60 (CH,COOH); Finnigan 32WE with Finnigan 6WO data system.
The mass spectrum of the sex attractant could not be recorded since
the content in the extract was extremely low. We estimate that only
ca. 0.1 ng was extracted from each female.
[7] W Knauf, 0 . Vostrowsky, H . J . Bestmann, unpublished.
Enantioselective Synthesis of Homoallyl Alcohols via
Chiral Allylboronic Esters
By Thomas Herold and Reinhard W Hofmann[*]
We report on the enantioselective synthesis of secondary
homoallyl alcohols of type (6) by a modification of the
["I
DipLChem. T. Herold, Prof. Dr. R. W. Hoffmann
Fachhereich Chemie der Universitat
Lahnberge, Postfach 1929
D-3550 Marburg I (Germany)
Anqew. Chem. I n t . Ed. E n g f . 17 (197s) No. 10
known1'] addition of allylboronic esters to aldehydes. This
procedure improves upon and supplements existing methods[''
for the enantioselective conversion of aldehydes into secondary
alcohols.
We used the glycol (2) [obtained from (+)-camphor via the
ketol
and its reaction with phenyllithium in ether] as
chiral matrix. Reaction of equimolar amounts of the allylboranes (3)['] and (2) (THF, 30min, 50°C) yielded more than
95 y, of the allylboronic esters ( - ) - ( 4 ) after vacuum distillation. A 2 M solution of ( 4 ) reacted (n-hexane, 1 h at -4O"C,
12h at 25°C) with an equivalent amount of an aldehyde
to give the borates ( 5 ) , from which the alcohols ( 6 ) were
obtained directly by cleavage with 1.2equiv. of triethanolamine
(2h, 25°C) (Table 1).
zaldehyde, however, and other aldehydes with a ( s p 2 - C j C H O
structure the values range from 24 to 54 %.
Received: July 20, 1978 [Z 57 IE]
German version: Angew. Chem. YO, 822 (1978)
CAS Registry numbers:
( - ) - ( I j, 23963-16-8; ( + ) - ( 2 ) , 67814-35-1; ( 3 0 ) . 688-61-9; (3g), 32784-73-9;
( - ) - ( 4 u ) , 67760-74-1 ;( - ) - ( 4 b ) , 67760-75-2; (Sa), 67760-76-3; ( S b ) , 6776017-4; (Scj, 67760-78-5; (Sdj, 67784-50-3; ( S e ) , 67784-49-0; (Sf). 67760-79-6;
(Sg), 67760-80-9; ( S h ) , 67760-81-0; ( 5 i ) , 67760-82-1; ( S j ) , 67760-83-2; ( 5 k ) ,
67784-53-6; ( 6 a ) . 64584-92-5; ( 6 b ) , 62959-96-0; ( 6 c ) , 67760-84-3; ( 6 d ) ,
67760-85-4; (6ej, 67760-86-5; ( 6 f ) , 67760-87-6; (69), 67760-88-7; ( 6 h ) ,
67760-89-8; (6i), 67760-90-1 ; ( 6 j ) , 67760-91-2; ( 6 k j , 67760-92-3; acetaldehyde, 75-07-0; propanal, 123-38-6; butanal, 123-72-8; 2-methylpropanal,
78-84-2 ;2,2-dimethylpropanaI,630-19-3
;2-chloro-2-methylpropanal, 91 7-93-1
[I] B. M. Mikhailoc, Organomet. Chem. Rev. A 8 , 1 (1972).
[2] 3. D. Morrison, H . S . Mosher: Asymmetric Organic RedCtiOnS, PrenticeHall, Englewood Cliffs, N. J., 1971; D. Seebach er al., Helv. Chim. Acta
60,301 (1977); R. Rossi, Synthesis 1978,413; H . Eichenauer, E. Friedrich,
W Lutz, D. Enders, Angew. Chem. YO, 219 (1978); Angew. Chem. Int.
Ed. Engl. 17, 206 (1978).
[3] I . Fleming, R. B. Woodward, J. Chem. SOC.C1968, 1289.
[4] J . A . Duie, D. L. Dull, H. S . Mosher, J. Org. Chem. 34, 2543 (1969);
3. A. Dale, H . S. Mosher, J. Am. Chem. SOC. 95, 512 (1973).
Functional Derivatives of D- and L-Ribose by Optical
Resolution with Recycling[**]
Except in the case of ( 6 f ) , the alcohols (6) were purified
by vacuum distillation; the chiral glycol (+)-(2) was recovered
in approximately 80% yield by chromatography on silica
gel with CH2C12. The whole sequence (2)- (6) can also
be effected in a one-pot process without isolation of intermediates.
Table 1. Enantiomeric excesses and yields in the synthesis of the alcohols
(6).
R'
(6a)
(6b)
(6c)
(6d)
(6e)
(6f)
(6g)
(6h)
(6ij
(6j)
(6k)
Me
Et
n-Pr
i-Pr
t-Bu
(CH3)2CCI
Me
Et
n-Pr
i-Pr
t-Bu
R2
H
H
H
H
H
H
Me
Me
Me
Me
Me
[2]6'
6.35
4.74
+10.37
- 2.62
- 5.32
-22.16
- 5.15
5.13
+23.08
- 1.40
- 3.10
-
+
+
c soh.
e.e.
Yield
[a1
[%I [bl
[%I [.I
9.13 E
10.76 B
10.22B
11.82 B
10.90 B
9.43 D
8.35 E
3.51 E
2.60 E
8.46 E
8.39 E
65 (R)
77(R)
72(R)
70 (S)
45 (S)
70 (S)
74(R)
70(R)
65 (R)
76 (S)
70 (S)
92
91
93
88
85
83
82
85
84
87
92
[a] Solvents: E=diethyl ether, B = benzene, D=dichloromethane. [b] The
enantiomeric excess of the alcohols (6) was determined in most cases by
I9F-NMR spectroscopy according to Mosher [4]. [c] Isolated yields of (6)
based on ( - ) - ( 4 ) .
The enantiomeric excesses are surprisingly constant for various aldehydes with a (sp3-C)-CHO structure. With benAngrw. Chem. Int. Ed. Enyl. 17 11978) N o . 10
By Richard R. Schmidt and Albrecht Lieberknecht"]
Starting from furan and the readily accessible vinylene carbonate['] we have developed a chirally economic synthesis[']
of the functional D- and L-riburonic acid derivatives ( 6 a )
and ( 6 bIC3l.These compounds are valuable intermediates
for the synthesis of biologically important nucleosides and
nucleoside uronic
and sugar-amino acid
Five straightforward reaction steps without isolation of intermediates transform the rneso-Diels-Alderadduct ( 1 )['] (mixture of diastereomers) into the cyclic meso-anhydride (5) (purified by distillation) in 40 % overall yield (Table 1). Compound
(1) is specifically transformed by osmium tetroxide into the
exo,exo-dihydroxy derivative, which is subsequently isopropylidenated at the hydroxy groups; removal of the carbonate
protecting group by barium hydroxide and oxidation by potassium permanganate converts the mixture of diastereomers
into the sterically uniform meso-l,5-anhydroallaric acid (2)
which contains the principal configurational components of
D- and L-ribose[6];reaction with acetic anhydride gives the
meso-anhydride ( 5 ) , which assumes a key role in the further
synthesis.
Reaction of ( 5 ) with trimethylsilyl azide quantitatively
yields a racemate of the ribofuranosyl isocyanates ( 6 a ) and
( 6 b ) . This reaction removes the meso structure of (5) and
irreversibly generates a mixture of enantiomers which reacts
with methanol to give the enantiomeric urethanes ( 7 a ) and
(7b).
[*I Prof. Dr. R. R. Schmidt
Fachbereich Chemie der Universitat
Postfach 7733, D-7750 Konstanz (Germany)
DipLChem. A. Lieberknecht
Institut fur Organische Chemie der Universitat
Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
[**I De-nouo Synthesis of Sugars, Part 2. This work was supported by the
Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie.-Part 1: R. R. Schmidt, R . Angerbauer, Angew. Chem. 89, 822 (1977);
Angew. Chem. Int. Ed. Engl. 27, 783 (1977).
769
Документ
Категория
Без категории
Просмотров
0
Размер файла
234 Кб
Теги
chiral, synthesis, esters, allylboronic, enantioselectivity, homoallylic, alcohol, via
1/--страниц
Пожаловаться на содержимое документа