Process for the preparation of mono-, bi- or poly-functional...

Details Process for the preparation of mono-, bi- or poly-functional... Process for the preparation of mono-, bi- or poly-functional...

2001-10-16

2004-02-03

McKane, Joseph K. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Nitriles

C558S431000, C585S457000

Reexamination Certificate

active

06686495

ABSTRACT:

INTRODUCTION AND BACKGROUND
The present invention relates to a process for the preparation of biaryls using active nickel, palladium or platinum catalysts.
Biaryl compounds, especially biphenyl compounds, are of commercial importance as fine chemicals, intermediates for pharmaceuticals, optical brightening agents and agrochemicals.
A frequently used method of synthesising biaryls is the Suzuki reaction, in which iodo- or bromo-aromatic compounds as well as aryl triflates and, more rarely, chloroaromatic compounds are reacted with aryl-, vinyl- or alkyl-boronic acid derivatives in the presence of palladium catalysts. An overview article describing this method is, for example, M. Beller, C. Bolm, Transition Metals for Organic Synthesis, Vol. 1, p. 208, VCH-Wiley, Weinheim 1998.
Suitable catalysts for use within the scope of the Suzuki reaction are generally palladium and nickel compounds. Despite the economic advantage of nickel catalysts, palladium catalysts are preferred over nickel catalysts because of their lower toxicity and their greater tolerance towards functional groups. In the case of the use of palladium catalysts, both palladium(II) and palladium(0) complexes are used in Suzuki reactions. According to the literature, there are formulated as the active catalytic species coordinatively unsaturated 14-and 16-electron palladium(0) species, which are stabilized with donor ligands such as phosphanes. In particular when more inexpensive educts such as aryl bromides or aryl chlorides are used, the addition of stabilizing ligands is required in order to achieve adequate catalytic activation of the starting materials.
The catalyst systems described for Suzuki reactions frequently exhibit satisfactory catalytic turnover numbers (TON) only with uneconomical starting materials such as iodoaromatic compounds and activated bromoaromatic compounds. Otherwise, in the case of deactivated bromoaromatic compounds (i.e. bromoaromatic compounds having “electron-displacing” substituents or sterically hindered bromoaromatic compounds), and especially in the case of chloroaromatic compounds, large amounts of catalyst—normally over 1 mol. %—must be added in order to achieve commercially usable turnovers.
In addition, because of the complexity of the reaction mixtures, simple catalyst recycling is impossible, so that catalyst costs generally also stand in the way of commercial realization. Although catalyst systems based on water-soluble phosphanes give satisfactory catalyst activities for the industrially important reaction of 2-chlorobenzonitrile with p-tolylboronic acid, the catalysts contain expensive sulfonated phosphanes. Moreover, a number of chloroaromatic compounds cannot as yet be activated in a commercially satisfactory manner even with those catalysts.
More recent active catalyst systems are based on cyclopalladated phosphanes (W. A. Herrmann, C. Bro&bgr;mer, K. Öfele, C. -P. Reisinger, T. Priermeier, M. Beller, H. Fischer,
Angew. Chem.
1995, 107, 1989;
Angew. Chem. Int. Ed. Engl.
1995, 34, 1844) or mixtures of sterically demanding arylphosphanes (J. P. Wolfe, S. L. Buchwald,
Angew. Chem.
1999, 111, 2570;
Angew. Chem. Int. Ed. Engl.
1999, 38, 2413) or tri-tert.-butylphosphane (A. F. Littke, G. C. Fu,
Angew. Chem.
1998, 110, 3586;
Angew. Chem. Int. Ed. Engl.
1998, 37, 3387) with palladium salts or palladium complexes.
However, inexpensive chloroaromatic compounds cannot generally be activated in a commercially satisfactory manner with those catalysts either, since the catalyst productivities (TON) are below 10,000 and the catalyst activities (TOF) are below 1000 h
−1
. Accordingly, in order to achieve high yields in particular in the case of such industrially valuable starting materials, it is necessary to use comparatively large and hence very expensive amounts of catalyst. For example, the catalyst costs for the preparation of one kilogram of an organic intermediate having a molecular weight of 200 using 1 mol. % palladium catalyst are more than 100 US$ at current noble metal prices, which shows the necessity of improving catalyst productivity. Accordingly, despite all the further developments made to catalysts in recent years, only a small number of industrial reactions of the arylation of chloroaromatic compounds have become known to date.
For the reasons mentioned, there is a great need for new processes for the preparation of biaryls, which processes do not exhibit the disadvantages of the known catalytic processes, and for palladium catalyst systems suitable therefor which contain inexpensive ligands, which are suitable for implementation on an industrial scale and which yield the biaryls in a high yield, with high catalyst productivity and in high purity.
SUMMARY OF THE INVENTION
That object can be achieved by a process for the preparation of mono-, bi- or poly-functional biaryls of the general formula I
Ar—Ar′  (I)
by reaction of an aryl compound of formula II
Ar—X  (II)
with an arylboronic acid derivative of formula III
Ar′—B(OR
1
)
2
  (III)
in the presence of a catalyst, which process is characterised in that the catalyst used is a metal complex of the general formula IV
wherein in formulae I to IV
Ar and Ar′ each independently of the other represents mono- or poly-cyclic aromatic that is optionally substituted as desired and has up to 14 carbon atoms in the ring, or heteroaromatic that is optionally substituted as desired and has from 5 to 10 atoms in the ring, of which up to four atoms independently of one another may be N, O or S,
X represents I, Br, Cl, OSO
2
CF
3
, OSO
2
(aryl), OSO
2
(alkyl), N
2
+
,
M represents nickel, palladium or platinum,
L represents a monodentate phosphoroorganic ligand PR
6
R
7
R
8
,
A, B, C each independently of the others represents oxygen, sulfur, CH
2
, C(R
9
)
a
(R
10
)
b
, N(R
11
)
c
, Si(R
12
)
d
(R
13
)
e
, wherein a, b, c, d, e may each independently of the others be 0 or 1, and when a, b, c, d, e of at least one of the radicals in question is 0, A, B and C may also be part of a ring system,
x, y, z represent 0 or 1 and x+y+z=from 1 to 3,
R
1
represents hydrogen, alkyl, aryl or alkenyl, wherein in formula III B(OR
1
)
2
may also form a ring system,
R
6
to R
8
have the meanings of R
1
, or represent O-alkyl, O—C(O)-alkyl, O-(aryl), as well as groups of any desired condensed ring system,
R
2
to R
5
.
and R
9
to R
13
have the meanings of R
1
, or represent O-alkyl, O—C(O)-alkyl, O-(aryl), O—C(O)-aryl, F, Cl, OH, NO
2
, Si (alkyl)
3
, CF
3
, CN, CO
2
H, C(O)H, SO
3
H, NH
2
, NH(alkyl), N(alkyl)
2
, P(alkyl)
2
, SO
2
(alkyl), SO(alkyl), SO(aryl), SO
2
(aryl), SO
3
(alkyl), SO
3
(aryl), S-alkyl, S-aryl, S-alkenyl, NH—CO(alkyl), CO
2
(alkyl), CONH
2
, CO(alkyl), NHCOH, NHCO
2
(alkyl), CO(aryl), CO
2
(aryl), CH═CH—CO
2
(alkyl), CH═CH—CO
2
H, P(aryl)
2
, PO(aryl)
2
, PO(alkyl)
2
, PO
3
H, PO(O-alkyl)
2
, and groups of any desired condensed ring system,
 wherein alkyl represents hydrocarbon radical having from 1 to 10 carbon atoms and alkenyl represents mono- or poly-unsaturated hydrocarbon having from 1 to 10 carbon atoms, each of which may be branched and/or substituted by Cl, F, alkyl, O-alkyl, phenyl, O-phenyl, and aryl represents an optionally Cl-, F-, alkyl-, O-alkyl-, phenyl-, O-phenyl-substituted aromatic or heteroaromatic having from 5 to 10 atoms in the ring.
In the process according to the invention, aryl compounds of formula II are preferably reacted with arylboronic acid derivatives of formula III in which Ar and Ar′ each independently of the other represents an optionally substituted phenyl, naphthyl, anthryl, phenanthryl or biphenyl.
In the process according to the invention, the aryl compounds used are preferably compounds of formula IIa
wherein R
14
to R
18
have the meanings given for R
2
to R
5
and R
9
to R
13
, and the arylboronic acid derivatives used are preferably compounds of formula IIIa
wherein R
19
to R
23
have the meanings given for R
2
to R
5
and R
9
to R
13
.
There are used as the

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