According to various workers [1-4], ethyl diazoacetate (EDA) reacts with various ... aration of the ethyl ester of 3-morpholyl-3-methylpentene-4-carboxylic acid (V) ...
REACTION OF ETHYL DIAZOACETATE WITH ~=LYLAMINES
CATALYZED
BY COPPER AND RHODIUM COMPLEXES UDC 542.97:547.235.4:547. 333:547.466.5'262
U. M. Dzhemilev, R. N. Fakhretdinov, R. M. Marvanov, and O. M. Nefedov
According to various workers [1-4], ethyl diazoacetate (EDA) reacts with various olefins in the presence of copper- and rhodium-containing catalysts to form derivatives of cyclopropanecarboxylic acids (CCA). In order to develop methods for the preparation of CCA containing aminoalkyl substituents in the side chain, we studied the catalytic reaction of EDA with the following allylic compounds: l-morpholyl-2-butene (I), 2-morpholyl-3-butene (If), l-morpholyl-2,7-octadiene (III), and l-piperidyl-2,7-octadiene (IV). Preliminary experiments showed that, under our experimental conditions, al]y]amines (I) and (II) react with EDA to give esters of linear unsaturated amino acids (V) and (VI) which are insertion products of ethoxycarbonylcarbene at the active allylic C--H bond. All attempts to direct the reaction toward the formation of CCA by changing the ratio of the starting reagents and the catalyst and altering the reaction conditions were unsuccessful. The reaction of (I) with EDA in 2:1 ratio at 20~ over 18 h in benzene by the action of the Cu(acac)2--P(OC6H4CH3-p)3-AIEt3 catalytic system (].:2:4 reagent ratio) leads to the preparation of the ethyl ester of 3-morpholyl-3-methylpentene-4-carboxylic acid (V) and 2-morpholyl-3-butene (II) in 69:3] ratio in ~80% total yield. The structure of (II) was confirmed by comparison with a known sample [5], while the structure of ester (V) follows from the IR, PMR, and mass spectral data. The IR spectrum of (V) has bands at 920, 1000, 1730, and 3080 cm -~ which are characteristic for the vinyl and ester groups. The PMR spectrum of ester (V) has two three-proton methyl group signals at 0.91 and 1.2 ppm. The methylene protons located between the ester group and the quaternary carbon atom as well as the morpholJne ring protons in the a position to the nitrogen atom correspond in intensity to six protons and give a multiplet at 5 2.45 ppm. lhe narrow four-proton multiplet at 3.47 ppm is assigned to the OCH2 group protons of the morpholine ring. lhe methylene protons in the ester group at the oxygen atom give a quartet at 4.05 ppm, while the olefinic protons (3H) via a signal at 4.8-5.6 ppm. The molecular weight of (V) found by mass spectroscopy is 227. The formation of (V) likely proceeds in two steps. Initially, (I) undergoes skcletal isomerization to give (II) by the action of copper complexes and then (II) reacts with EDA to give (V). In order to check this hypothesis, we studied the reaction of (II) with EDA under the conditions described above. This reaction was found to proceed with the formation of a mixture of ester (V), the ethyl ester of 3-morpholylhexene-4-carboxylic acid (VI), and amine (I) in 16:75:9 ratio in about 20% total yield. Thus, as in the experiment with (I), the formation of amino ester (V) is observed although in much lower yield. =-
(v)
+(If)
(I) + Cu--L n
Cu--L n + ( I I )
: N~CHCO~Et
/~-~
.0~
.,~
9
~ N - - ( ~ / +(V)+(1) ~ CH2C02Et (W)
These results indicate that ~r-allylic copper complexes of copper, tive dissociation of the--C-aN~ and C--H bonds in amines
1
per ions, apparently participate
formed by the oxida-
(I) and (Ii) by the action of the cop-
in the formation of (V) and (VI) from (I) or (If) and EDA.
Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 588-593, March, Original article submitted December 20, 198].
0568-5230/84/3303-0539508.50
9 1984 Plenum Publishing Corporation
Translated 1984.
539
The reaction is probably accomplished by a mechanism, in which allylamines (VII) and (VIII) coordinate at the central atom of the catalyst with cleavage of the C-~N or C--H bond, which leads to the formation of o,~-allylic (IX) or hydride complexes (X) and (XI). Under the reaction conditions, complex (IX) is converted into allylamines (VII) and (VIII). Hydride complexes (X) and (XI) react with EDA to form (XII) and (XIII). Subsequent doubling of the activated o-fragments in complexes (XII) and (XIII) leads to amino esters (XIV) and (XV). The low yields of amines (V) and (VI) from (II) are apparently related to the presence of a bulky branched alkenyl substituent in (II), which hinders the approach of the lowvalence complexes to the reaction site. These results, aswell as the data of Vitenberg [6] and Moser [7], indicate that EDA under our reaction conditions apparently decomposes by the action of copper cations to form complexes such as (XII) and (XIII). Subsequent transformations of (XII) and (XIII) lead to the corresponding amino acid esters (XIV) and (XV). It is not excluded that free ethoxycarbonylcarbenes take part
i~tr col
'
(VII) RRIN~_ L,, ,
,
\cu,.
(IX) (x)
H--Cu'~-'L,~
~NzCHCO2EI
RRIN~.~...L n(X]'I) H~CHCO2Et
~Cu-Ln
RR~N-~ (X1V) CH2CO2Et
> Rw:
