A possible way to control the course of hydride transfer in allylation of norbornadiene in the presence of palladium phosphine catalysts

Article abstract of DOI:10.1007/s11172-016-1629-z

Features of allylation of norbornadiene (NBD) with allyl formate were investigated in the presence of Pd catalysts. In addition to the products of single or double allylation and hydroallylation of NBD, the products of secondary transformations, hydration and hydroformylation, have been found. An effect of triphenylphosphine on the reaction direction was studied.

Full text of DOI:10.1007/s11172-016-1629-z

Russian Chemical Bulletin, International Edition, Vol. 65, No.11, pp. 2639—2643, November, 2016
2639
A possible way to control the course of hydride transfer in allylation
of norbornadiene in the presence of palladium phosphine catalysts
V. R. Flid, S. A. Durakov, and T. A. Morozova
Moscow Technological University (Institute of Fine Chemical Technology),
86 prosp. Vernadskogo, 119571 Moscow, Russian Federation.
Fax: +7 (499) 600 8300. Eꢀmail: vitalyꢀflid@yandex.ru.
Features of allylation of norbornadiene (NBD) with allyl formate were investigated in the
presence of Pd catalysts. In addition to the products of single or double allylation and hydroꢀ
allylation of NBD, the products of secondary transformations, hydration and hydroformylꢀ
ation, have been found. An effect of triphenylphosphine on the reaction direction was studied.
Key words: norbornadiene, allyl formate, palladium acetate, allylation, hydroallylation,
homogeneous metal complex catalysis.
Reactions of allyl esters of carbonic acids (Scheme 1)
take a special place in the catalytic chemistry of biꢀ
cyclo[2.2.1]heptaꢀ2,5ꢀdiene (norbornadiene, NBD).1—3
Unique structures of the adducts account for the
features of the reaction mechanism:4,5 addition of allyl
fragment to NBD yields methylene vinyl derivative (1)
or products in which this fragment inserts into methylꢀ
enecyclobutane (2) or methylenecyclohexane (3) ring.
In all cases, allyl group loses hydrogen atom which is
removed with carboxylic acid. In the case of excess of
the allylating agent in the reaction mixture, comꢀ
pounds 1 and 2, which retain a double bond inside the
cycle, undergo secondary allylation resulting in the isoꢀ
mers 4—6 (Scheme 2).
Using allyl formate (AF) in the reaction in the presꢀ
ence of Pd complexes gives rise to 5ꢀallylbicyclo[2.2.1]ꢀ
Scheme 1
M = Ni, Pd
R = Me, Et, But, Ph, CCl , CF3
3
Scheme 2
M = Ni, Pd
R = Me, Et, But, Ph, CCl , CF3
3
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2639—2643, November, 2016.
1066ꢀ5285/16/6511ꢀ2639 © 2016 Springer Science+Business Media, Inc.

2640
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Flid et al.
heptꢀ2ꢀene (7) (Scheme 3). Moreover, in the absence of
phosphine ligands, this product predominates.6
Results and Discussion
Palladium(II) acetate (Pd3(OAc)6) was applied as
a precursor of the catalyst and triphenylphosphine (TPP)
was added to it in various ratio. The reaction between
equimolar amounts of NBD and AF give compounds,
composition of which shows a wider variety of products
than product distribution observed in similar reactions of
other allyl esters (Scheme 4).
Scheme 3
The main reaction products are compounds 1, 2, 3 and
7 with molecular weights of 132 and 134. The yields of
these compounds depend on the reactant ratio, catalyst
composition and reaction conditions (Table 1).
The products of the double allylation of NBD (comꢀ
pounds 4—6) with molecular weights of 172 are also obꢀ
served. Other compounds are formed when only AF is used
and have molecular weights of 174 and 176 and result from
hydroallylation of compounds 1, 2, 7. Those are mainly
regioꢀ and stereoisomers 9—11. Compounds 12—14 with
a molecular weight of 134 are produced via hydrogenation
of compounds 2 and 3. In this case, the most active double
bond inside the cycle participates in the reaction. The
products of hydrogen attachment to methylene groups have
been not found under the given conditions. In addition to
the substances indicated above the products of hydroꢀ
formylation of NBD, compounds 15 and 16, were detectꢀ
ed. The total yield of the products of the secondary reacꢀ
tions does not exceed 30%.
A principal difference between the reactions shown in
Schemes 1 and 3 is a course of hydride transfer. In the first
case, allyl ligand is attached to NBD as С3Н4 fragment, so
it loses a hydrogen atom (oxidative allylation). In the
second case, hydroallylation takes place, i.e. reductive
allylation, in which NBD molecule formally attaches С3Н6
fragment. Pd complexes catalyze both reactions. Thereby,
a study of particularities in behavior of palladium phosꢀ
phine catalytic systems is significant for clarifying the
mechanism of hydride transfer and process selectivity.
Relationships between quantative characteristics of allylꢀ
ation of NBD with methyl formate and composition of
the catalytic system have never been investigated earlier.
Scheme 4

Allylation of norbornadiene
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2641
Table 1. The results of the reaction between NBD and AF at various mole ratio of TPP : Pd in argon atmosphere*
TPP : Pd
Conversion (%)
NBD AF
Selectivity (%)
Contribution of the products
of single allylation (%)
1
2
3
7
8
Products of
secondary
reaction
C
10H12
C10H14
No phosphine
1 : 3
1.5 : 3
2 : 3
3 : 3
4 : 3
95
77
78
80
79
78
78
77
97
98
99
99
99
98
99
99
—
14
19
23
24
25
26
22
—
16
15
14
14
14
14
12
18
17
18
20
20
20
22
22
91
30
27
23
19
16
11
19
1
1
2
3
2
2
3
5
—
22
19
17
21
23
24
30
9
61
67
72
75
79
86
87
91
39
33
28
25
21
14
13
5 : 3
6 : 3
* С0NBD = С0AF = 0.5 mol L–1, Pd : NBD = 1 : 100, T = 25 °C, τ = 48 h, acetonitrile is applied as a solvent.
Thus, we selected the basic conditions at which reacꢀ
tion between NBD and AF can follow two mechanisms.
First one results in the products of oxidative allylation
С10Н12), whereas the second one leads to the products of
reductive allylation (С10Н14). The mechanism depends
on the molar ratio of TPP : Pd. At an equimolar ratio of
NBD to AF and high conversions of the reactants, secꢀ
ondary reactions involving the products of single allylaꢀ
tion of NBD occur. Thereby, it is interesting to study the
effect of TPP introduced into catalytic system on the
course of the process when it is kinetically controlled. The
highest selectivity to the products of single allylation of
NBD is achieved at the reactant conversion of 30%
(τ = 2.5 h) (Table 2). Further growth in conversion signifꢀ
icantly increases the amount of products of double allylꢀ
ation of NBD from the compounds which retained the
intracycle double bond.
of the products of oxidative allylation of NBD (comꢀ
pounds 1—3). The total yield of compound 7 is remarkꢀ
ably improved. Nevertheless, increase in conversion of
NBD and AF (see Table 1) increases the yield of the prodꢀ
ucts of secondary processes involving compounds 1, 2 and
7 (double allylation, hydrogenation and hydroformylꢀ
ation). Since compound 3 has no intracycle double bond,
it is not active in following reactions.
Maximum selectivity to the products of oxidative allylꢀ
ation is attained with a double excess of the TPP in
TPP : Pd ratio. Further rise of the amount of phosphine
decreases the conversion of the reactants up to 10—15%.
This experimental fact may be accounted for by the forꢀ
mation of Pd(PPh3)4. complex which is inactive under the
given conditions.
It has been shown earlier that the mechanism of interꢀ
action between NBD and allyl esters of carbonic acids is
complicated. The first step of the process is oxidative adꢀ
dition of the ester to palladium to form πꢀallyl PdII comꢀ
plex. Then allyl fragment undergoes π—σꢀisomerization,
In the absence of TPP in the catalytic system, a high
selectivity (91%) to compound 7 is achieved. Elevating
the TPP : Pd ratio considerably enhances the contribution
Table 2. The results of the reaction between NBD and AF at various mole ratio of TPP : Pd in argon atmosphere*
TPP : Pd
Conversion (%)
NBD AF
Selectivity (%)
Contribution of the products
of single allylation (%)
1
2
3
7
8
Products of
secondary
reaction
C
10H12
C10H14
No phosphine
1 : 3
1.5 : 3
2 : 3
3 : 3
4 : 3
28
29
28
29
29
28
28
29
28
30
29
30
30
30
30
31
—
18
20
24
27
30
32
33
—
21
25
27
25
25
24
26
18
23
24
23
23
24
23
23
91
36
29
24
22
18
17
13
1
1
1
1
2
1
2
3
—
1
1
1
1
2
2
2
9
64
71
76
78
82
83
87
91
36
29
24
22
18
17
13
5 : 3
6 : 3
* С0NBD = С0AF = 0.5 mol L–1, Pd : NBD = 1 : 100, T = 25 °C, τ = 2.5 h, acetonitrile is applied as a solvent.

2642
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016
Flid et al.
Scheme 5
L = NBD, MeCN
and coordination of NBD molecule with metal atom takes
place. Afterwards, the way of the process may differ deꢀ
pending on structure of allyl ester and presence of phosꢀ
phine ligands.5—9
ative allylation of NBD is likely to be directly associated
with an effect of various palladium complexes which are
different in the number of phosphine ligands in the coorꢀ
dinating sphere of palladium (Scheme 6).
As it was described above, the reaction of AF with
NBD over palladium catalyst without TPP admixture gives
the product of hydroallylation on NBD (compound 7)
with high selectivity. The mechanism of this process might
be related to the hydrogen transfer from the formyl fragꢀ
ment and generation of the hydride complex of palladium,
ensuing conversion of which brings about the formation of
compound 7 and dioxide carbon as well as regeneration of
the catalyst (Scheme 5).
The results on regularities in generation of the product
of oxidative allylation of NBD (compounds 1—3) are simꢀ
ilar to the experimental results on the process performance
in the presence of nickel phosphine catalysts.10 The present
experiments reveal quantative effect of the ligands inside
the coordination sphere of the metal on the course of
βꢀhydride transfer.
Experimental
These reactions are observed when other allyl esters
are used. Therefore, catalytic hydroallylation of NBD with
allyl formate is unique and application of phosphine
ligands may radically change the course of hydride transꢀ
fer in the process of interest.
Moreover, molar ratio of TPP : Pd seems to exert
a relevant effect on the ratio of compounds 1—3 in the reacꢀ
tion products. The resulting product composition in oxidꢀ
NBD and allyl formate were used with a purity grade of
≥99.5%. Pd3(OAc)6 produced by the known procedures11,12 was
applied as a catalyst precursor. Triphenylphosphine (Aldrich)
was recrystallized from a methanol—chloroform mixture (4 : 1,
vol.; 15 mL g–1) in nitrogen atmosphere. Acetonitrile, used as
a solvent, was distillated over Р2О5 before the experiment.
The reactions were performed in a thermostated evacuating
reactor equipped with a magnetic stirrer and a sampling device.
After all the components were mixed, oxygen was removed
from the reactor and the reaction was carried out in argon atmoꢀ
sphere at 25 °С.
Scheme 6
Product composition was controlled by gas chromatography
using a Kristall PMꢀ2000 instrument equipped with an Agilent
J&W HPꢀ50+ capillary column (Agilent Technologies) and
a flameꢀionization detector. GC/MS analysis and 1Н and
13С NMR spectroscopy served to identify the resulting comꢀ
pounds. GC/MS analysis was performed on a 689 ON gas chroꢀ
matograph (Agilent Technologies) equipped with a massꢀselective
detector and a CPS CPꢀSyl 5 capillary column. NMR spectra
were recorded on a Bruker DPX 300 instrument (1H, 300.13 MHz;
13С, 75.033 MHz). The data of the earlier published works1—6,13
were applied at spectra interpretation.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 14ꢀ03ꢀ00419).
References
1. M. Catellani, G. P. Chiusoli, G. J. Salerno, Organomet.
Chem., 1979, 177, 29.
2. U. M. Dzhemilev, R. I. Khusnutdinov, D. K. Galeev, O. M.
Nefedov, G. A. Tolstikov, Bull. Acad. Sci. USSR, Div. Chem.

Allylation of norbornadiene
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 11, November, 2016 2643
Sci. (Eng. Transl.), 1987, 36, 122 [Izv. Acad. Nauk USSR,
Ser. Khim., 1987, 138].
3. E. M. Evstigneeva, O. S. Manulik, V. R. Flid, Kinet. Catal.
(Eng. Transl.), 2004, 45, 172 [Kinetika i Kataliz, 2004,
45, 188].
4. V. F. Flid, E. M. Evstigneeva, O. Yu. Tkachenko, R. S.
Shamsiev Zh. Ros. khim. obshchestva im. D. I. Mendeleeva,
2006, 50, No. 4, 93 [Mendeleev Chem. J. (Engl. Transl.),
2006, 50, No. 4].
8. E. M. Evstigneeva, R. S. Shamsiev, V. R. Flid, Vestnik
MITHT [MITHT Bulletin], 2006, 3, 3 (in Russian).
9. X. Hujun, F. Ting, L. Qunfang, W. Fang, Sci. China Chem.,
2016, 1.
10. V. R. Flid, O. S. Manulik, D. V. Dmitriev, V. B. Kouznetsov,
E. M. Evstigneeva, A. P. Belov, A. A. Grigor´ev, Eurasian
Chem. Tech. J., 2001, 3, 201.
11. J. Tsuji, in Palladium Reagents and Catalysis, John Wiley and
Sons, New York, 1996, p. 549.
5. I. P. Stolyarov, A. E. Gekhman, I. I. Moiseev, A. Yu.
Kolesnikov, E. M. Evstigneeva, V. R. Flid, Russ. Chem. Bull.
(Int. Ed.), 2007, 56, 309 [Izv. Acad. Nauk, Ser. Khim.,
2007, 320].
6. E. M. Evstigneeva, V. R. Flid, Russ. Chem. Bull. (Int. Ed.),
2008, 57, 837 [Izv. Acad. Nauk, Ser. Khim., 2008, 823].
7. M. Rosales, I. Pacheco, J. Medina, J. Fernandez, A. Gonzaꢀ
lez, R. Izquierdo, L. G. Melean, P. J. Baricelli, Catal. Lett.,
2014, 144, 1717.
12. I. P. Stolyarov, L. I. Demina, N. V. Cherkashina, Russ. J.
Inorg. Chem. (Engl. Transl.), 2011, 10, 1532 [Zh. Neorg.
Khim., 2011, 10, 1611].
13. R. I. Khusnutdinov, N. A. Shchadneva, L. F. Mukhametꢀ
shina, Russ. J. Org. Chem., 2010, 46, 54 [Zh. Org. Khim.,
2010, 46, 54].
Received June 10, 2016;
in revised form August 16, 2016