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Mechanism of the Oxo Synthesis.

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part of the DNA with formation of derivatives of structure
UV
( 2 ) and
mutations
then deamination
and mutations
to ( Iinduced
).
by ionizing radiation
can thus be interpreted by means of the same primary irradiation product.
Lecture at Saarbriicken (Germany) on February 9, 1968
[VR 152 IE]
German version: Angew. Chem. 80, 536 (1968)
[*] Prof. Dr. E. Fahr
lnstitut fur Organische Chemie der Universitat
87 Wiirzburg, Rontgenring 11 (Germany)
%
‘H
3
$%CH3
H
li
CH302C H
H
OH
CH30zC H
H
%
: CH3
0
0
CH302C
0
H O
(8)
I 7)
(6)
H “H
Lecture at Braunschweig (Germany) on February 12, 1968 [VB 153 IE1
German version: Angew. Chem. 80, 536 (1968)
[ * ] Prof. Dr. E. Winterfeldt
Synthesis and Configuration of Heterocyclic lndole
Derivatives. The Stereoselective Total Synthesis
of DL-Akuadgine and DL-Tetrahydroalstonine
Organisch-Chemisches Institut der Technischen Universitat
1 Berlin 12, Strasse des 17. Juni 115 (Germany)
[l] Cf: E. Winterfeldt and H . Radunz, Anyew. Chem. 79, 1023
(1967); Angew. Chem. internat. Edit. 6, 1003 (1967).
By E. Winterjeldt [*I
Mechanism of the 0 x 0 Synthesis
The a,@-unsaturated ketone ( I ) is useful for synthesis of
heterocyclic indole alkaloids of type ( 3 ) . Michael addition
of malonic ester and subsequent reduction by BH40 affords
the lactones of type (2)’ which can be converted into ( 3 ) by
reduction and loss of water 111.
By J . Falber*1
Although the 0x0 reaction (conversion of olefins into aldehydes by CO/H2) was discovered by 0. Roelen in 1938 111 and
the annual world capacity of such plants will exceed 1.5 x 106
tons in 1968, the mechanism of the reaction is not yet fully
clarified.
Many proposed mechanisms had to be discarded because
they could not be brought into accord with the equation set
up by G. Nuttu et al. [21 for the kinetics of the reaction:
A reaction route by way of carbonium ions had to be rejected
because the carbon chain was not isomerized in the reaction.
A reaction involving radicals is also unlikely because reaction
is not hindered by radical-trapping agents such as iodine and
sterically hindered phenols.
A scheme proposed by R . F. Heck et ul. [31 is largely in accord
with the kinetics of the 0x0 reaction:
HCo(C0)a G HCo(C0)3
+
CO
(1)
In the stereoselective preparation of (2) the Michael addition
to ( 1 ) occurs with simultaneous formation of a cis-quinolizidine system. Compound ( 4 ) . with the axial acetyl group, is
the product obtained under kinetic control and on treatment
with alkali affords the thermodynamically favored product
( 5 ) containing equatorial substituents.
HCo(C0)s
+
H2CzCH2
+
HzCyCHz
(2)
HCo(C0)3
+ co
H~C-CH~-CO(CO)S
H ~ C - C H ~ - C O ( C O )(4)
~
H ~ C - C H ~ - C O ( C O3
)~
H ~ C - C H ~ - C - C O ( C(5)
~)~
II
0
‘C02CH3
(4)
Under thermodynamic control, compound ( 5 ) is thus obtained stereospecifically.
The keto group can also be reduced stereospecifically. Compound ( 4 ) reacts with BH4e to give exclusively (61, whereas
compound ( 5 ) with BH4e in the cold gives mainly (7) but
with Li[AIHz(OR)2] in tetrahydrofuran gives mainly ( 8 ) . The
configurations follow from the I R and N M R data.
Reduction and dehydration of the sterically homogeneous
lactones gives compounds of type ( 3 ) with the cis-quinolizidine system which are convertible into trans-quinolizidines
by dehydrogenation [with Pb(OAc)4] and subsequent reduction with BH4e. In this way compound ( 4 ) yields DL-akuammigine stereospecifically and then DL-tetrahydroalstonine
by reversal of configuration at C-3.
552
H B C - C H ~ - $ - C O ( C O )+~ Hz
0
-
(6)
H ~ C - C H Z - C H O+ HCo(C0)s
However, all attempts to detect tricarbonylhydridocobalt or
alkyltricarbonylcobalt compounds under the conditions of
the 0x0 reaction have failed. Recent investigations also indicate that a course involving (1)-(3) is doubtful since the 0x0
reaction occurs also at high pressure where the equilibrium
in (1) should lie wholly to the left-hand side; against this
mechanism is also the fact that the reaction can be carried
out in the presence of complexes of the type HCo(C0)3PR3
in which the metal-carbon bond is so strong that loss of CO
and formation of a coordinatively unsaturated carbonyl
under the conditions of the reaction seem unlikely.
Angew. Chem. internut. Edit. i VoL 7 (1968) 1 No. 7
Equations (7) and (8) are therefore proposed as alternatives
to (1)-(4).
H C O ( C O ) ~ L+ H2C=CH2
-e-
HzC=CHz
L
HCo(C0)3L
I n most of the known 0 x 0 reactions tetracarbonylhydridocobalt reacts as the hydride; it may react as protonic acid in
the 0x0 reaction of epoxides.
r
(7)
0
/ \
HzC=CHz
i
H C o (CO)3 L
H~C-CHZ-CO(CO)~L
(8)
HzC-CHz
+
Y"
1
H C O ( C O ) ~+
L = CO, PR3
The x-complex formulated in (7) may occur as dsp3-hybrid in
the form of a trigonal bipyramid, in which the hydrogen is
bonded as hydride ion in the outer sphere and cobalt has
formally a single positive charge. The Co-alkyl compound
pictured in (8) may also be a trigonal-bipyramidal dsp3-hybrid.
One of the factors promoting conversion of the alkyl into the
acyl compound (equation 5 ) is to be found in the decrease in
steric hindrance o n the conversion dsp3 (trigonal bipyramid)
+ sp3 (tetrahedral). The mechanism proposed also agrees
well with the isomerizations of Co-alkyl and -acyl compounds experimentally established as occurring during the
0x0 reaction, whereby according to Orchin ef al. [41 a hydrogen shift from the ally1 position occurs.
f;I
HCo
r
H ~ C = C H - C H R .+
Compounds that d o not possess hydrogen in theallyl position
d o not isomerize.
+
HCo(C0)4
[VB 154 IE]
Lecture at Berlin on February 12, 1968
German version: Angew. Chern. 80, 568 (1968)
[*] Dr. J. Falbe
Ruhrchemie AG.
42 Oberhausen-Holten, Bruchstrasse (Germany)
[l] 0. Roelen, DRP 849548 (1938),Chem. Zbl. 1953,927; US-Pat.
2327060 (1943); Chem. Abstr. 38, 550 (1944); Belg. Pat. 436625
(1939); Chem. Zbl. 1941 I, 1354; French Pat. 860289 (1939),
Chem. Zbl. 1941 11, 536; 0.Roe/en, Angew. Chem. A 60, 213
(1948); 0. Roelen, in K . Ziegler: Naturforschung und Medizin in
Deutschland, Vol. 36, Praparative organische Chemie, Part 1.
p. 157. Dieterich'sche Verlagsbuchhandlung, Wiesbaden 1948.
121 G. Natfu, R. Ercoli, and S. Castellano, Chim. e Ind. (Milano)
37, 6 (1955).
[3] D . S. Breslow and R . F. Heck, Chem. and Ind. 1960, 461;
R. F. Heck and D . S . Breslow, J. Amer. chem. SOC. 83, 4023
(1961).
[4] L. Karupinka and M . Orchit?, J. org. Chemistry 26, 4187
(1961).
Photolysis and Radiolysis of Carbon Monoxide in
the Gaseous, Liquid, and Solid State at 298"K,
77"K, and 20.4"K
By W. Groth t *I
With vinyl chloride and dihydropyran the primary addition
of cobalt to the C = C double bond and the subsequent isomerization occur in different directions:
H,C=CH-+
HCo(C0)
a+
b(CO)&o-CHz-CH2-C1
H&cH=C~
@
@
In the gas phase CO is excited by light quanta (Kr or Xe
resonance wave lengths, I line at 2062 A, Hg sensitization)
or y-rays first to thea3n-state and then reacts with CO in the
ground state to give COz and C3O2. Excitation of the Alll
state and of triplet states of CO by the K r and Xe resonance
wavelengths can be detected by fluorescence studies.
Pure liquid C O is not decomposed by the 2062 A I line. In
CO-CH4 mixtures ethane and acetaldehyde are formed by
way of excited CO molecules.
In the y-radiolysis of CO at 298 "K addition of noble gases
shows that ionic reactions d o not occur but that electronically
excited C O moIecules play an important part in the primary
process. The dependence of G(C02) o n the pressure can also
be explained by means of excited CO molecules which can
pass into another excited state.
Radiolysis of pure liquid C O at 77 OK gives CO2 with G(C02)
of 0.22, but n o C3O2 is formed. In CO-CH4 mixtures there
are formed, besides C 0 2 and C302, also aldehydes, ketene,
ethane, and acetylene, whose mode of formation has been
clarified by use of isotope techniques. In mixtures of C O and
0 2 there are formed in the liquid phase (77 OK) COz, C3O2,
and 0 3 , but in the solid phase (20.4'K) only CO2 and 0 3 .
The dependence of the G values for COz. C3O2, and 0 3 are
explained for the liquid phase by assuming various excited
states of C O (Aln, higher triplet states, axn), and for the
solid phase by assuming intermediate formation of CO3.
Lecture at Gottingen (Germany) on February 15, 1968
[VB 155 IEl
German version: Angew. Chem. 80, 538 (1968)
[*I Prof. Dr. W. Groth
Institut fur Physikalische Chemie der Universitat
53 Bonn, Wegelerstr. 12 (Germany)
Angew. Chem. internat. Edit. f Vol. 7 (1968) / No. 7
553
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