Cross-coupling reactions of aryl and vinyl chlorides catalyzed by a palladium complex derived from an air-stable H-phosphonate

Article abstract of DOI:10.1039/b518283b

A palladium complex derived from air-stable TADDOLP(O)H catalyzes efficiently Hiyama, Stille, Kumada and Suzuki cross-coupling reactions of aryl and vinyl chlorides. The Royal Society of Chemistry 2006.

Full text of DOI:10.1039/b518283b

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Cross-coupling reactions of aryl and vinyl chlorides catalyzed by a
palladium complex derived from an air-stable H-phosphonate{
Lutz Ackermann,* Christian J. Gschrei, Andreas Althammer and Melanie Riederer
Received (in Cambridge, UK) 4th January 2006, Accepted 1st February 2006
First published as an Advance Article on the web 21st February 2006
DOI: 10.1039/b518283b
Important functional groups, such as an ester (entry 2), a nitro-
substituent (entry 4), (enolizable) ketones (entries 5 and 6) and a
cyano-group (entry 7) were tolerated.
A palladium complex derived from air-stable TADDOLP(O)H
catalyzes efficiently Hiyama, Stille, Kumada and Suzuki cross-
coupling reactions of aryl and vinyl chlorides.
Remarkably, TADDOL derivative 8 allowed for cross-coupling
reactions between aryl chlorides and various organometallic
species as pronucleophiles. Thus, Stille (entry 8), Kumada (entries
Transition metal-catalyzed cross-coupling reactions are useful
tools for the synthesis of compounds with sp2–sp2 linkages, which
are valuable building blocks in natural products, liquid crystals,
polymers and ligands.1,2 Iodides and activated bromides can be
successfully transformed employing simple metal salts. Aryl
chlorides are more useful substrates due to their lower cost and
the wider diversity of available compounds. The conversion of aryl
chlorides requires recently developed stabilizing ligands.
Predominantly, the ligand design focused on electron-rich tertiary
phosphines.3 A notable alternative makes use of alkyl-substituted
secondary phosphine oxides4 as preligands.5,6 We reported the first
use of modular air-stable heteroatom-substituted secondary
phosphine oxides as preligands for cross-coupling reactions of
aryl chlorides.7 Diaminophosphine oxides allowed also for efficient
nickel-catalyzed C–F bond activation reactions at ambient
temperature8 as well as ruthenium-catalyzed C–H bond arylation
reactions using aryl chlorides.9 Herein, we present the first
Table 1 Performance of palladium catalysts derived from secondary
phosphine oxides
Nr Preligand
Yielda (%)
—
1
2
—
—
4
5
10 mol% (18)b
application of
a
palladium complex derived from an
3
10 mol%
—
H-phosphonate to cross-coupling reactions between silicon-, tin-,
magnesium- or boron-based organometallic species and aryl
chlorides.10
At the outset of our studies, we probed the catalytic activity of
palladium complexes derived from different heteroatom-substi-
tuted secondary phosphine oxides in Hiyama cross-coupling
reactions with aryl chloride 1a (Table 1). In contrast to our
studies on Suzuki coupling reactions,7 diaminophosphine oxide 4
gave unsatisfactory conversion of chloride 1a (entry 2). Sterically
congested preligand 5, previously employed in nickel-catalyzed
Kumada cross-coupling reactions,8 gave inferior results (entry 3).
However, H-phosphonates 711 and 812 enabled isolation of
pyridine 3 with good yields (entries 5–8). The influence of Pd/
preligand ratio was found to be less pronounced, with an optimal
ratio of 1/2 (entry 8).
4
5
6
7
10 mol% (25)b
10 mol% (51)b
With an optimized catalyst in hand, we probed its application to
the conversion of diversely substituted aryl chlorides in Hiyama
cross-coupling reactions (Table 2, entries 1–7).{
6
7
8
8
20 mol% (57)b
5 mol% 61
10 mol% 63
Department Chemie und Biochemie, Ludwig-Maximilians-Universita¨t
Mu¨nchen, Butenandtstrasse 5-13, Haus F, 81377, Mu¨nchen, Germany.
E-mail: Lutz.Ackermann@cup.uni-muenchen.de;
Fax: (+49) 089 21 80 774 25
{ Electronic supplementary information (ESI) available: Experimental
section. See DOI: 10.1039/b518283b
a
1a (1.00 mmol), 2a (2.00 mmol), TBAF (2.00 mmol), [Pd(dba)2]
b
(5.0 mol%), dioxane (2 mL), 80 uC, 17 h, isolated yields. By GC
analysis versus n-decane as internal standard.
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Table 2 Palladium-catalyzed cross-coupling reactions with aryl and vinyl chlorides 1 (see Scheme 1)a
Nr
1
R
Pronucleophile
Product
Yield (%)
3-py
3a
63
2
3
4
5
4-MeO2CC6H4
4-F3CC6H4
4-O2NC6H4
3-AcC6H4
3b
3c
3d
3e
68
62
79
71
6
7
4-PhC(O)C6H4
2-NCC6H4
3f
65
3g
60b
8
9
4-O2NC6H4
3-MeC6H4
3d
3h
72b
73
10
11
2-MeC6H4
3i
3j
61
86
3,5-(MeO)2C6H3
12
3,5-(MeO)2C6H3
3k
95
13
14
3l
3f
85
74
4-PhC(O)C6H4
1420 | Chem. Commun., 2006, 1419–1421
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Table 2 Palladium-catalyzed cross-coupling reactions with aryl and vinyl chlorides 1 (see Scheme 1)a (Continued)
Nr
15
R
Pronucleophile
Product
Yield (%)
92
4-F3CC6H4
3c
3a
16
3-py
95
a
General reaction conditions: Hiyama and Stille reaction: 1 (1.00 mmol), 2 (2.00 mmol), TBAF (2.00 mmol), [Pd(dba)2] (5.0 mol%), 8
(10.0 mol%), dioxane (2 mL), 80 uC. Kumada reaction: 1 (1.00 mmol), 2 (1.50 mmol), [Pd(OAc)2] (2.0 mol%), 8 (4.0 mol%), THF (2 mL),
60 uC. Suzuki reaction: 1 (1.00 mmol), 2 (1.50 mmol), [Pd(dba)2] (2.0 mol%), 8 (4.0 mol%), KOt-Bu (3.00 mmol), THF (5 mL), 60 uC. Isolated
b
yields. By GC analysis versus n-decane as internal standard.
Notes and references
{ Representative procedure for palladium-catalyzed Hiyama cross-cou-
pling reactions of aryl chlorides (Table 2, entry 4): A solution of [Pd(dba)2]
(29 mg, 0.05 mmol, 5.0 mol%) and 8 (51 mg, 0.10 mmol, 10.0 mol%),
4-chloronitrobenzene (0.158 g, 1.00 mmol), phenyltrimethoxysilane (2a)
(0.397 g, 2.00 mmol) and TBAF (0.631 g, 2.00 mmol) in dry dioxane (2 mL)
was stirred for 17 h at 80 uC. Et2O (50 mL) and H2O (50 mL) were added
to the reaction mixture. The separated aqueous phase was extracted with
Et2O (2 6 50 mL). The combined organic layers were dried over MgSO4
and concentrated in vacuo. The remaining residue was purified by column
chromatography on silica gel (n-pentane/Et2O = 50/1A30/1) to yield 3d
(0.157 g, 79%) as a light yellow solid.
Scheme 1 Cross-coupling reactions with a palladium complex derived
from TADDOLP(O)H (8) (see Table 2).
1 A. de Meijere and F. Diederich, Metal-Catalyzed Cross-Coupling
Reactions, 2nd edn., Wiley-VCH, Weinheim, 2004.
2 M. Beller and C. Bolm, Transition Metals for Organic Synthesis, 2nd
edn., Wiley-VCH, Weinheim, 2004.
3 A. F. Littke and G. C. Fu, Angew. Chem., Int. Ed., 2002, 41, 4176–4211.
4 For a highlight article on the use in enantioselective transition metal-
catalyzed transformations, see: N. V. Dubrovina and A. Bo¨rner, Angew.
Chem., Int. Ed., 2004, 43, 5883–5886.
5 G. Y. Li, Angew. Chem., Int. Ed., 2001, 40, 1513–1516.
6 Selected examples for the use of alkyl-substituted secondary phosphine
oxides in palladium-catalyzed coupling reactions: (a) Hiyama reaction:
C. Wolf and R. Lerebours, Org. Lett., 2004, 6, 1147–1150; (b)
R. Lerebours and C. Wolf, Synthesis, 2005, 2287–2292; (c) Stille
reaction: C. Wolf and R. Lerebours, J. Org. Chem., 2003, 68,
7551–7554; (d) Kumada reaction: G. Y. Li, J. Organomet. Chem.,
2002, 653, 63–68; (e) Suzuki reaction: G. Y. Li, J. Org. Chem., 2002, 67,
3643–3650 and references cited therein.
7 L. Ackermann and R. Born, Angew. Chem., Int. Ed., 2005, 44,
2444–2447.
8 L. Ackermann, R. Born, J. H. Spatz and D. Meyer, Angew. Chem., Int.
Ed., 2005, 44, 7216–7219.
9 L. Ackermann, Org. Lett., 2005, 7, 3123–3125.
10 For a single example of a cross-coupling between an aryl chloride and a
boronic acid, see ref. 7.
11 X. Linghu, J. R. Potnick and J. S. Johnson, J. Am. Chem. Soc., 2004,
126, 3070–3071.
9–13) and Suzuki (entries 14–16) reactions were efficiently
catalyzed. Functionalized aryl chlorides gave rise to the
corresponding biphenyls in good yields of isolated product
(entries 8 and 14). Furthermore, the air-stable catalyst was
applicable to the use of heterocyclic (entries 1 and 16) as well as
vinylic chlorides (entry 13). Importantly, the protocol was not
limited to electron-poor substrates, but allowed also for the use of
electron-rich, thereby electronically deactivated, aryl chlorides
(entries 9–12).
In conclusion, we present the application of an efficient
palladium catalyst derived from H-phosphonate TADDOLP-
(O)H (8) to cross-coupling reactions between aryl and vinyl
chlorides and various organometallic species. The results reported
herein represent the first use of an air-stable heteroatom-
substituted secondary phosphine oxide in Hiyama and Stille as
well as palladium-catalyzed Kumada cross-coupling reactions.
Support by the Fonds der Chemischen Industrie, the Ludwig-
Maximilians-Universita¨t, and Professor P. Knochel is acknowl-
edged. We thank the DFG for substantial financial support within
the Emmy Noether-Program.
12 D. Enders, L. Tedeschi and J. W. Bats, Angew. Chem., Int. Ed., 2000, 39,
4605–4607.
This journal is ß The Royal Society of Chemistry 2006
Chem. Commun., 2006, 1419–1421 | 1421