Amphiphilic catalytic allylating reagent, bis-π-allylpalladium complex

Full text of DOI:10.1021/ja971599e

J. Am. Chem. Soc. 1997, 119, 8113-8114
8113
Amphiphilic Catalytic Allylating Reagent,
Bis-π-allylpalladium Complex
Table 1. Palladium Catalyzed Double Allylation of Activated
Olefins 3 with Allyltributylstannane 4 and Allyl Chloride 5
Hiroyuki Nakamura, Jae-Goo Shim, and
Yoshinori Yamamoto*
Department of Chemistry, Graduate School of Science
Tohoku UniVersity, Sendai 980-77, Japan
ReceiVed May 19, 1997
π-Allylpalladium complexes 1 react with various nucleophiles
to construct carbon-carbon or carbon-heteroatom bond, and
the so-called Tsuji-Trost type reaction via 1 is well recognized
1
as a very important modern organic transformation. We
previously found that bis-π-allylpalladium complex 2 reacts with
electrophiles such as aldehydes and imines to produce carbon-
2
,3
carbon bond in a manner different from the reaction via 1.
Herein we wish to report that bis-π-allylpalladium complex acts
as the first amphiphilic catalytic allylating agent; it reacts with
both nucleophilic and electrophilic carbons at once to produce
4
double allylation products in high to good yields (eq 1).
The reaction of phenylethylidene malononitrile 3a (1 equiv),
allyltributylstannane 4 (1.2 equiv), and allyl chloride 5 (1.2
equiv) in THF was carried out in the presence of PdCl2(PPh3)2
(3 mol %) under Ar atmosphere, and the results are shown in
eq 2 and Table 1 (entry 1). NMR yield of 6a was 99% yield,
and it was isolated in 91% yield (entry 1). The use of 5 mol %
and 1.5 mol % of the catalyst also gave 6a in 99% and 98%
NMR yields, respectively. The use of allyl chloride gave higher
yields in comparison with that of allyl bromide. Although
tetrakis(triphenylphosphine)palladium was as an efficient cata-
a
Isolated yields based on 3. Diastereomer ratios were indicated in
the parentheses and the stereochemistries of those diastereomers were
not determined. b 1H NMR yield was 99%. c 10 mol % of the catalyst
was used.
5
lyst as dichlorobis(triphenylphosphine)palladium, other catalysts
such as Pd(dba)2, or its diphosphine complexes, Pd(OAc)2, and
PdCl2(PBu3)2, gave 6a in lower yields. Acetonitrile or N,N-
dimethylformamide was an equally effective solvent as THF
for the double allylation reaction. In all cases, monoallylated
products were not obtained.6
(1) Tsuji, J. In Palladium Reagents and Catalysts; John Wiley and Son:
Chichester, 1995; p 61. Codleski, S. A. In ComprehensiVe Organic Synthesis;
Semmelhack, M. F., Ed.; Pergamon Press: Oxford, 1991; Vol. 4, p 585.
Collman, J. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G. In Principles
and Applications of Organotransition Metal Chemistry; Mill Valley, 1987;
p 417.
(
2) Nakamura, H.; Asao, N.; Yamamoto, Y. J. Chem. Soc., Chem.
Commun. 1995, 1273. Nakamura, H.; Iwama, H.; Yamamoto, Y. J. Chem.
Soc., Chem. Commun. 1996, 1459. Nakamura, H.; Iwama, H.; Yamamoto,
Y. J. Am. Chem. Soc. 1996, 118, 6641, and references cited therein.
(3) Although π-allylpalladium-X complexes 1 in which X is an electron
withdrawing group react with nucleophiles, it is also known that certain
π-allyltransition metal complexes react with electrophiles. π-Allylmolyb-
denum complexes: Faller, J. W.; Nguyen J. T.; Ellis, W.; Mazzieri, M. R.
Organometallics 1993, 12, 1434. Faller, J. W.; DiVerdi, M. J.; John, J. A.
Tetrahedron Lett. 1991, 32, 1271. Faller, J. W.; Linebarrier, D. L. J. Am.
Chem. Soc. 1989, 111, 1937. π-Allylnickel complexes: Hegedus, L. S.;
Wagner, S. D.; Waterman, E. L.; Siirala-Hansen, K. J. Org. Chem. 1975,
The activated olefins (3b-d) underwent the double allylation
very smoothly to give the corresponding 1,7-octadienes (6b-
d) in high yields (entries 2-4). However, only trace amounts
of desired compound 6e were obtained in the reaction of
tetrasubstituted olefin 3e. Not only the activated olefins having
two CN groups (3a-d) but also those bearing CN and CO2Et
(3f-i) or CN and SO2Ph (3j-k) underwent the double allylation
4
0, 593. π-Allyltitanium complexes: Sato, F.; Iijima, S.; Sato, M.
Tetrahedron Lett. 1981, 22, 243. Collins, S.; Kuntz, B. A.; Hong, Y. J.
Org. Chem. 1989, 54, 4154.
(
4) Ohno, K.; Mitsuyasu, T.; Tsuji, J. Tetrahedron Lett. 1972, 28, 3705.
5) The use of tetrakis(triphenylphosphine)palladium gave 6a in 99%
(6) The use of Ni(PPh3)4 as a catalyst in THF gave a monoallylated
product (Michael type product) in 70% yield along with small amounts
(∼9%) of 6a.
(
yield under the same coditions.
S0002-7863(97)01599-0 CCC: $14.00 © 1997 American Chemical Society

8114 J. Am. Chem. Soc., Vol. 119, No. 34, 1997
Communications to the Editor
Scheme 1
7. The reductive coupling from 7 would give the corresponding
1,7-octadienes 6 and palladium(0) species. At this stage, π-allyl
group of 7 reacts with a nucleophilic carbon center. The
oxidative insertion of Pd(0) into allyl chloride would produce
the π-allylpalladium complex 8. When Pd(PPh3)4 was used as
a catalyst instead of PdCl2(PPh3)2, the catalytic cycle would
start from the Pd(0) species. The reaction of 8 with allylstan-
nane would produce 2 and Bu3SnCl.
In organic chemistry, a few amphiphilic reagents are known,8
,9
but we believe that catalytic amphiphilic reagents and reactions
1
0
are unprecedented. Further extension of the double catalytic
allylation is now in progress.
Supporting Information Available: Experimental data for 6a-d
and 6f-l (6 pages). See any current masthead page for ordering and
Internet access instructions.
JA971599E
reaction, giving the corresponding octadienes (6f-k) in good
yields (entries 6-11), although the diastereoselectivities of the
reactions were not high. Even an olefin 3l, activated by a single
CN group, gave the double allylation product 6l in an allowable
yield (entry 12).
(
7) It has been confirmed that the reaction between allyltributylstannane
and PdCl2(PPh3)2 produces bis-π-allylpalladium complex. See ref 2.
(
8) The stoichiometric reaction of bis-π-allylpalladium complex with CO2
and SO2 was reported; Hung, T.; Jolly, P. W.; Wilke, G. J. J. Organomet.
Chem. 1980, 190, C5.
(
9) Amphiphilic substrates are well-known, for example, see: Lee, V.
A mechanistic rationale which accounts for the unprecedented
double allylation of activated olefins is shown in Scheme 1.
The transmetalation of allyltributylstannane to palladium would
J. In ComprehensiVe Organic Synthesis; Semmelhack, M. F., Ed.; Perga-
mon: Oxford, 1991, Vol. 4, pp 69-137, and references cited therein.
(10) One referee posed a question whether bis-π-allylpalladium is really
catalytically active or not. The meaning of “catalytic” in the title is that
bis-π-allylpalladium is produced catalytically, although its reaction with 3
proceeds stoichiometrically.
7
produce bis-π-allylpalladium complex 2, which would react
with activated olefins 3 to give the π-allylpalladium intermediate