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Oxidation of -Unsaturated Esters and Lactones with Selenium Dioxide to -Oxo or -Hydroxy Derivatives; Synthesis of (▒)-A 26771 B and Norpyrenophorin.

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Oxidation of a$-Unsaturated Esters
and Lactones with Selenium Dioxide to
y-0x0 or y-Hydroxy Derivatives;
Synthesis of (+)-A 26771 B and Norpyrenophorin
9a, n
=
8; 9b, n = 10
Diels-Alder adducts of a$-unsaturated esters 5 may be
obtained directly via a four-component reaction in a reaction bomb at 120°C. Examples include the syntheses with
2,3-dimethylbutadiene 10 and cyclopentadiene 12 as diene
components (Table 2).
CIHB-OH
+
+
C,H,-CHO
lb
3
1-
+
10
2a
By Huns Jurgen Bestmum* and Ruiner Schobert
Dedicated to Professor Huns Musso on the occasion oj
his 60th birthday
y-0x0-a$-unsaturated esters 2 are interesting synthetic
building blocks, for example, for [2 +4] cycloadditions. We
have found that these compounds are easily accessible via
oxidation of a,B-unsaturated esters"] with S e 0 2 in anhydrous dioxane.[21Chiral esters such as 2c are of particular
interest for enantioselective c y c l ~ a d d i t i o n s . ' ~ ~
When the reaction is carried out in dioxane containing
3% water, the y-hydroxy-a$-unsaturated esters 3[41are obtained. Table 1 gives several examples.
"./\/
11
+
~ 1 - 0 ~ R~-CHO
1
+
3
120oc
0x2
+
2
12
3
h
Table I. Esters 2 [a] and 3 [b] via oxidation of cr,(l-unsaturated esters 1 with
selenium dioxide.
13
Table 2. Muconic esters 7 and unsaturated macrocyclic lactones 9 via threecomponent synthesis; cycloadducts 11 and 13 via four-component synthesis.
80
73-75/0.01 [a]
(34-35)[b]
(166)[b]
7a
n-C,H9
7b
(-)-Menthy1
-
80
9a
9b
-
11
---
13a
13b
(n-C',H,)2CH
(-)-Menthy1
n-C,H7
C2Hs
60-65
60-65
51
55
101/0.01
90/0.01
58
110/0.01
~
~
58/0.01
78.5/0.02
- 83
(c=O.S)
-
-
R'
Yield['%]
n-CIHI
n-C3H7
C'H,
n-C,H7
C2H,
CH,
n-C,,H 1 3
n-C,H,,
(-)-Menthy1
n-ChH I 3
CH(n-C,H7)2
(-)-Menthy1
89
90
78
52
61
60
B.p.["C'/torr]
92/0.01
76/0.0 I
Y9/0.0? [c]
[dl
10510.0 1
132/0.01 [el
[a] S e 0 2 (14 mmol) is added to a solution of 1 (10 mmol) in ca. 100 m L of dry
dioxane, and the mixture is heated under inert atmosphere for 48 h. The selenium is filtered off, the filtrate is concentrated, and the residue is purified by
distillation or chromatography. [b] The same procedure is used as in [a] except that ca. 3 mL of water is added to the reaction mixture. [c] [a]?: -59.6
( c = 1.0; EtOH). [d] Chromatographic purification on silica gel 60: R , =0.44
(hexanelether 3 : 1). [el [a]:: -77.8 ( c = 1.1 I , CHCI,).
- 53.8
(c= 1.16)
[a] Kugelrohr. air-bath heating. [bl From hexane.
A stereochemically pure cycloadduct 11 is formed from
butanol l b , pentanal Sa, 3, and 10. The bicyclo[2.2.l]heptene derivatives 13 are obtained as diastereomeric mixtures (13a, 77 :23 ; 13b, 80 :20). A definite endo-exo assignment has not yet been possible.
Received: April 10, 1985 [ Z 1260 IE]
German version: Angew. Chem. 97 (1985) 783
[ I ] H . J. Bestmann, D. Sandmeier, Angew. Chem. 87 (1975) 630; Angew.
Chem In/. Ed. Engl. 14 (1975) 634; Chem. Eer. 113 (1980) 274.
[2] H. J . Bestmann, K. G. Schmid, D. Sandmeier, Chem. Ber. 113 (1980)
912.
131 Mechanism: H. J. Bestmann, Pure Appl. Chem. 52 (1980) 771: H. J . Bestmann, 0. Vostrowsky. Top. Curr. Chem. 109 (1983) 85.
14) W. Oppolzer, Angew. Chem. 96 (1984) 840; Angew. Chem. Int. Ed. Engl.
23 (1984) 876: G. Helmchen, R. Schmierer, ibid. 93 (1981) 208 and 20
(198 I) 205.
15) H. J. Bestmann, R. Schobert,Angew. Clirm. 95 (1983) 810: Angew. Chem.
In,. Ed. Engl. 22 (1983) 780.
Angew. Chem. I n r . Ed. Enyl. 24 (1985) No. 9
2a
2b
2c
3a
3b
3c
R'
A number of macrolide antibiotics are y-0x0 or y-hydroxy-n,p-unsaturated lactones, e.g., c y t o ~ h a l a s i n s pyre,~~~
nophorins,[61the macrocycle A 26 77 1 B,"] and brefeldin
A.Lx1
The use of selenium dioxide oxidation in the synthesis
of such compounds is illustrated by the following examples.
(+)-A26771 B 8 : The hydroxy aldehyde 4 undergoes
cyclization with ketenylidenetriphenylphosphorane 5 to
give the +unsaturated
lactone 6."' Oxidation of 6 with
selenium dioxide gives the y-0x0 compound 7 , whose
transformation into the antibiotic 8 has already been de10O0C/O.05 torr; 7 : b.p.=93"C/0.05
s ~ r i b e d . ' ~(~6':~b.p.=
]
torr (kugelrohr, air-bath heating); 8 : m.p. = 131"C.)
Norpyrenophorin 14: The a$-unsaturated ester 11 is
obtained by three-component reaction"] of the tetrahydropyranyl ether 9 and the acetal 10 of o-hydroxypentanal
with 5 in benzene and its protecting groups are then
[*I
Prof. Dr. H. J. Bestmann, Dip1.-Chem. R. Schobert
lnstitut fur Organische Chemie der Universitat Erlangen-Nurnberg
Henkestrasse 42. D-8520 Erlangen (FRG)
0 V C H Verlaysgesellschaft mbH, D-6Y40 Weinhem, 1985
0570-0833/85/0909-0791 $ 02.50/0
79 1
131 W. Oppolzer, Angew. Chem. 96 (1954) 840: Angew. Chem. In/. E d . Engl.
A
+ Ph,P=C=C=O
HO-CHCH,-(CH2),,-CHO
_j
23 (1984) 876.
[4] For the oxidation of an cz.13-unsaturated ester with selenium dioxide in
steroid aynthesis, leading to a hutenolide. see N . Danieli. Y . Mazour. F.
Sondheimer, Tetrahedron Lefr. /966. 3 189.
[ 5 ] C. Tamm, Front. B i d 46 (1978) 15.
[6] B. Seuring. D. Seebach, Liehigs A n n . Chem 1978, 2044.
171 K. H. Michel, P. V. Demarco, R. Nagarajan, J . Anrrhiot. 30 (1977) 571.
[8] V. L. Singleton, N. Bohonos, A. J. Ullstrup. Nature /London) 181 (1958)
1072: E. Hirri, W. Loeffler, H. P. Sigg, H. Stihelin. C. Tamm, Hell;.
Chim. Acto 46 (1963) 1235.
[9] M. Asaoka, N. Yanagida, H. Takei. Tetrahedron Let,. 21 (1980) 461 I.
[ 101 For further syntheses, see B. M. Trost, S. J. Brickner, J . A m . Chem. Soc.
105 (1983) 568.
[ I I ] For further syntheses, see, for example, R. S. Mali, M. Pohmakotr. B.
Weidmann, D. Seebach, Liebigs A n n . Chem. 1981. 2272.
65%
5
4
o 7
Chiral Poly(9,9'-spirobifIuorene) Crown Ethers
By Max Dobler. Miljenko DumiC. Martin Egli. and
Vladimir Prelog*
cleaved in acid. The w-hydroxy aldehyde 12 so formed is
not isolated but rather cyclized to the diolide 13 by addition of a ca. 0.1 M solution of 12 in xylene to the molar
equivalent amount of 5 in refluxing xylene (high-dilution
conditions)."' The subsequent oxidation of 13 with two
+5+
THPO-(CH,)4-CH0
0
HO-(CH2)4<
]
0
10
9
11
HO-(CH2)4*
COO-(CH2),-CHO
12
+ 5
___j
42%
0
13
14
0
equivalents of selenium dioxide affords norpyrenophorin
141"1 (11: b.p.= 125-128"C/O.O5 torr (kugelrohr, air-bath
heating); 13: m.p. = 5 5 T (hexane), b.p. = 127"C/0.01 torr;
14 : m.p. = 13 1 "C).
Received: April 10, 1985:
supplemented: May 15, 1985 (Z 1261 IE]
German version: Angew. Chem. 97 (1985) 784
CAS Registry numbers:
I ( R ' = n - C , H , R'=n-C,H,,), 97827-33-3: 1 (R'=n-C>H,, R'=n-C4Hy),
97827-34-4; I ( R ' = C I H , , R 2 = ( -)-menthyl), 97827-35-5; 1 ( R ' = C 2 H 5 .
R'=CH(n-C,H7)2. 97827-36-6: 1 ( R ' = C H , , R'=(-)-menthyl). 57564-56-4:
2a, 97827-37-7: 2b, 97827-38-8: 2c, 97827-39-9: 3a, 97827-40-2: 3b, 9782741-3: 3c, 97827-42-4: (+)-4, 97827-43-5: 5, 15596-07-3; ( + ) - 6 , 97827-44-6;
( k ) - 7 , 77413-26-4: (k)-S, 56448-20-5: 9, 14194-86-6; 10, $3516-55-6; 11,
97827-45-7: 12, 97827-46-8: 13, 97827-47-9: 14, 69604-23-5.
[ I ] H. J . Bestmann, R. Schobert. Angew. Chem. 97 (1985) 783; Angew.
Chem. Int. E d . Engl. 24 (1985) 790.
[Z] Other methods of synthesis: H. J. Bestmann, F. Seng, H. Schulz, Chem.
Ber. 96 (1963) 465: H. J . Bestmann, G. Graf, H. Hartung, Justus Liebigs
Ann. Chem. 706 (1967) 68.
792
0 V C H Verlagsgeselbchaft mhH. 0-6940 Weinheim. 1985
The first two members of the poly(9,9'-spirobifluorene)
crown ether series, bis(9,9'-spirobifluorene)-[26]crown-4 4
and bis(9,9'-spirobifluorene)-[32]crown-6 5 , were initially
obtained as side products in the preparation of the corresponding mono(9,9'-spirobifluorene) crown ethers from
2,2'-bis(bromomethyl)-9,9'-spirobifluorene1 and the alkoxides of ethylene glycol and diethylene glycol, respectively."' Direct synthesis via condensation of 1 with alkoxides of the two dihydroxy ethers 2 and 3 in the presence of
potassium tert-butoxide affords the cyclic products only in
moderate, nonreproducible yields.
In the meantime, it has been found that the two bis(9,9'spirobifluorene) crown ethers 4 and 5 exhibit, as ionophores, high enantioselectivity for salts of biologically active a-amino alcohols (e.g., ephedrine),"] thus enhancing
their interest. We have attempted to improve the second
procedure of preparation of the compounds 4 and 5 by
modifying the reaction conditions. It was finally possible
to obtain 4 and 5 reproducibly in 40-50% yield by reaction
of I with the dihydroxy ethers 2 and 3, which may be prepared quantitatively, under the conditions of phase-transfer catalysis."
Upon investigation of the crude products by thin layer
chromatography, the two bis(9,9'-spirobifluorene) crown
ethers 4 and 5 were found to be accompanied by several
closely related compounds, which could be separated by
chromatography on silica gel. These compounds were
identified as poly(9,9'-spirobifluorene) crown ethers 6 to 9
on the basis of their UV, CD, NMR, and, in particular,
mass spectral4' and are summarized in Table I.
The crown ethers 6 to 9"l are striking in several respects. They are well-defined cyclic compounds with a
large number of ring members (52 to 104). They belong to
the class of chiral yet highly symmetrical compounds
(point group symmetry C,,, n = 4 , 6, 8), for which only a
few examples are known.lhl As crown ethers, they are potential host molecules. On account of their chirality, they
are expected to be enantioselective, like the compounds 4
and 5.I'I It is therefore advantageous that their sense of
chirality, or absolute configuration, is known.
Characteristic of the poly(9,9'-spirobifluorene) crown
ethers is the strong binding of solvent and crystallization
[*] Prof. Dr. V. Prelog, Priv.-Doz. Dr. M. Dobler, Dr. M. Dumik,
Dipl.-Chem. M. Egli
Lahoratoriuni fur Organische Chemie
der Eidgenossischen Technischen Hochschule
ETH-Zentrum, Universitatstrasse 16, CH-8092 Zurich (Switzerland)
0570-0833/85/0909-0792 $ 02.50/0
Angew. Chem. In/. E d . Engl. 24 11985) No. 9
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oxidation, synthesis, dioxide, lactones, norpyrenophorin, esters, unsaturated, selenium, oxo, derivatives, hydroxy, 26771
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