Catalytic [2+1]-cycloaddition of ethyl diazoacetate to fullerene [60]

Tuktarov, Airat R.; Akhmetov, A. F.; Kamalov, R. F.; Халилов, Л. М.; Pudas, Marko; Ибрагимов, А. Г.; Джемилев, У. М.

doi:10.1134/s1070428009080090

Cited by 20 publications

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“…Homofullerene III does not isomerize into metanofullerene II [9][10][11] in contrast to cycloadducts obtained by the cycloaddition of substituted diazomethanes or diazoacetates to C 60 -fullerene [11][12][13][14][15][16][17].…”

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Catalytic cyclopropanation of fullerene[60] with diazomethane

et al. 2009

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The selective cyclopropanation of C 60 -fullerene with diazomethane was performed under the catalysis with Pd(acac) 2 , and individual 5,6-open and 6,6-closed cycloadducts were obtained.The deep interest attracted by methanofullerenes is due to the prospects of their application as components of energy-rich fuel and also nanomaterials for produc-tion of modern additives for highly loaded mechanisms and machines, initial substances in the synthesis of drugs [1][2][3][4][5][6][7].In 1992 first information appeared on the possibility of [2+3]-cycloaddition of diazomethane to the [6,6]-bond of the C 60 -fullerene molecule with the formation of fulleropyrazoline I that under the conditions of thermal process converted into 5,6-open [2+1]-cycloadduct [8]. At a photochemical irradiation of the fulleropyrazoline a mixture was formed of 6,6-closed and 5,6-open adducts II and III in the ratio 3:4 [9]. Fulleropyrazoline I under the action of catalytic amounts of Pd(OAc) 2 (20 mol% Pd, toluene, 20°C, 8 h) transformed into individual 5,6-open fulleroid III. On increasing the reaction time to 30 h a mixture formed of 5,6-open, 6,6-closed adducts II and III, and unindentified fullerene derivatives in the ratiõ 2:1: 1 (HPLC). At the use of a stoichiometric quantity of Pd(OAc) 2 in the reaction of C 60 -fullerene with an ether solution of diazomethane (3-4 equiv of CH 2 N 2 , toluene, 0°C) methanofullerene II formed in ~15% yield [10].Homofullerene III does not isomerize into metanofullerene II [9][10][11] in contrast to cycloadducts obtained by the cycloaddition of substituted diazomethanes or diazoacetates to C 60 -fullerene [11-17].The above described syntheses of methanofullerenes posses a number of disadvantages related to the low yields of the target [2+1]-cycloadducts or with the necessity of preliminary preparation of fulleropyrazolines that only at heating, irradiation, or under the action of transition metal complexes are converted into methanofullerenes. Besides the selective synthesis of methanofullerene II from C 60 -fullerene and diazomethane required a stoichiometric amount of Pd(OAc) 2 .Proceeding from the above and aiming at development of a preparative method of catalytic cyclopropanation of C 60 -fullerene with diazomethane with the goal of obtaining methanofullerenes in high yields we investigated this reaction using as catalysts complexes of Cu, Pd, and Rh known as the most active and selective in diazocompounds cycloaddition to olefins [18][19][20][21][22][23][24][25][26].The diazomethane reaction with C 60 -fullerene provided the highest yield of the target methanofullerenes at the use as a catalyst Pd(acac) 2 . In this connection all subsequent experiments were carried out with this complex. In the reaction of ether solution of diazomethane with C 60 -fullerene [molar ratio 1:1, 20 mol% Pd(acac) 2 , 40°C, 5 min, toluene] fulleropyrazoline I formed in ~30% yield. The addition of 1 equiv more of diazomethane in ether resulted in an increase in the fullerene conversion to 60%. After 2 h the disappearence of f...

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Catalytic cyclopropanation of fullerene[60] with diazomethane

et al. 2009

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“…12 H (12″)). 13 C NMR, δ: 15.74 (MeC(10″)); 17.06 (MeC(8″)); 17.29 (MeC(19″)); 17.36 (MeC(4″)); 18.51 (C(6″)); 21.41 (MeC(20″)); 23.56 (C(11″)); 23.77 (C(16″)); 24.10 (MeC(14″)); 28.23 (C(15″)); 28.55 (MeC(4″); C(2″)); 30.91 (C(21″)); 33.10 (C(7″)); 36.81 (C(22″)); 37.06 (C(10″)); 37.99 (C(4″)); 38.61 (C(1″)); 39.14 (C(20″)); 39.20 (C(19″)); 39.65 (C(8″)); 39.71 (C(1´)); 42.07 (C(14″)); 47.64 (C(9″)); 48.06 (C(17″)); 51.35 (MeCO 2 ); 52.96 (C(18″)); 55.59 (C(5″)); 70.88 (C(2´) and C(3´)); 83.79 (C(3″)); 125.47 (C(12″)); 136.40, 138.28 (C(13″)); 140. 44 …”

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“…[ and MeC(12´´´)); 21.01 (C(4″)); 21.37 (C(2´´´)); 22.92 (C(13´´´)); 24.01 (MeC(2″) and C(10´´´)); 24.85 (C(6´´´)); 28.37 (C(12´´´)); 31.52 (C(3″)); 33.13 (C(3´´´)); 37.64 (C(9´´´)); 37.75 (C(7´´´)); 37.85 (C(5´´´)); 39.09 (C(1´)); 39.67 (C(11´´´)); 39.70 (C(4´´´) and C(8´´´)); 40.34 (C(1´´´)); 70.54 (C(2´) and C(3´)); 75.06 (C(2″)); 117.56 (C(5″)); 123.52 (C(7″)); 124.96 (C(8″)); 126.75 (C(4″a) 13.65 (MeAr); 21.17 (C(4″)); 25.59 (MeC(2″)); 30.47 (C(3″)); 39.00 (C(1´)); 52.18 (MeCO 2 ); 70.48 (C(2´) and C(3´)); 77.00 (C(2″)); 117.33 (C(5″)); 123.56 (C(7″)); 125.02 (C(8″)); 127. 12 H (12″)).…”

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confidence: 98%

Covalent binding of fullerene C60 to pharmacologically important compounds

2011

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“…Recently, 18 we have reported the synthesis of cyclo propafullerenecarboxylates with high yields by cycloaddi tion of ethyl diazoacetate to [60]fullerene in the presence of palladium complexes. In continuation of this research, in the present work we studied [2+1] cycloaddition of ethyl 2 alkyl(hetaryl) 2 diazoacetates and other substituted di azo compounds to [60]fullerene in the presence of palladi um complexes.…”

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Catalytic [2+1] cycloaddition of diazo compounds to [60]fullerene

et al. 2009

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A catalytic method for the efficient synthesis of 5,6 open and 6,6 closed (2π+1π) fullerene adducts by [2+1] cycloaddition of ethyl 2 alkyl(hetaryl) 2 diazoacetates to [60]fullerene in the presence of a three component catalyst Pd(acac) 2 -PPh 3 -Et 3 Al have been developed.Substituted cyclopropafullerenes are promising com pounds that could find applications in medicine and agri culture, as high energy fuel components and the heavy machinery lubricant additives. 1-13 Cyclopropafullerenes are usually obtained by cyclopropanation of fullerene with malonic acid derivatives following the Bingel proce dure, 14,15 as well as by thermal 16 or catalytic 17 [2+1] cy cloaddition of diazo compounds to [60]fullerene. The pub lished data 16,17 suggest that the known synthetic meth ods towards cyclopropafullerenes have low effectiveness or require stoichiometric amounts of such highly expen sive promoters as ruthenium complexes. Besides, the yields of the target compounds are low.The thermal cycloaddition reaction of diazoacetates to [60]fullerene yielded 5,6 open (homofullerenes) and 6,6 closed (methanofullerenes or cyclopropafullerenes) adducts in ~35% total yield. Separation of the reaction mixture into the individual adducts is very difficult and, in some cases, is not possible.Recently, 18 we have reported the synthesis of cyclo propafullerenecarboxylates with high yields by cycloaddi tion of ethyl diazoacetate to [60]fullerene in the presence of palladium complexes. In continuation of this research, in the present work we studied [2+1] cycloaddition of ethyl 2 alkyl(hetaryl) 2 diazoacetates and other substituted di azo compounds to [60]fullerene in the presence of palladi um complexes. The effect of the solvents and ratio of the catalytic system components as well as the bulkiness of the alkyl substituent in starting diazo compound on the yield and selectivity have also been studied. Results and DiscussionA three component catalyst prepared from Pd(acac) 2 , PPh 3 , and Et 3 Al turned out to be particularly efficient in the reaction under study showing the highest activity and selectivity among transition metal complexes tested. In this regard, all subsequent experiments were carried out using this catalytic system.It has been found that the reaction of ethyl 2 methyl 2 diazoacetate with [60]fullerene (molar ratio 5 : 1) in the presence of 20 mol.% of Pd(acac) 2 -PPh 3 -Et 3 Al (1 : 2 : 4) at 20 °C (18 h, o dichlorobenzene) resulted in a mixture of 6,6 closed (1) and 5,6 open (2) fullerene adducts along with the corresponding bis cyclopropane derivatives 3 and 4 in the ratio (1 + 2) : (3 + 4) ~3 : 1 in ~77% total yield (Scheme 1). No noticeable increase in the total yield (~79%) and changes in the ratio of adducts 1, 2 and 3, 4 were observed when the reaction time was prolonged up to 30 h. Similar results were obtained on increase in the reaction temperature to 40 and 80 °C with concomitant reduction of the reaction time from 18 to 1.5 and 0.5 h, respectively.The mixture of mono (1, 2) and bis adducts (3, 4) was separat...

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Catalytic [2+1]-cycloaddition of ethyl diazoacetate to fullerene [60]

Cited by 20 publications

References 16 publications

Catalytic cyclopropanation of fullerene[60] with diazomethane

Catalytic cyclopropanation of fullerene[60] with diazomethane

Covalent binding of fullerene C60 to pharmacologically important compounds

Catalytic [2+1] cycloaddition of diazo compounds to [60]fullerene

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