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Nucleophilic Attack on (-Allyl)palladium Complexes Direction of the Attack to the Central or Terminal Carbon Atom by Ligand Control.

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141 a ) t l W. RcicbkY, _I Mun7enherg. M. Nolteineyer. Aiigcw. C'/wiii. 1990. 102. 73:
4 i i w i i . C ' l i c i i i . Iiii 151. OigI. 1990. 2'1. 61 , b) J. Munienberg. H . W. Roeaky. S.
Lle\\ci-. R . Herhst-lrmer. C. M . Shcldrick. Iiiorg Chriii. 1992, 31, 2986
151 M Bpi-p\iii\\(in. T. Heinre. H. U: Roesky. F. Pauer. D Stalke, C. M .
Shcldi-ick. .-lii,yi'ii. C./ici?i. 1991. 1/13. 1671: A i i ~ c , i i .('/ic,iii. / i l l . Ed. Dig/. 1991.
30. I h 7 7
[O] A tla.is. hl Pryka. C'/ieiii. Be,-. 1995. 128. 11.
Y. (iao. M . P:irve/. .Ih i . C ~ l i w i Six..
.
1995. 117. 2359.
k: Vricfc. J. C'/iiwi. S o ( . C/imi. C ' o i ) i i i i i i i i . 1976. 64: h) .I Kuyper.
I. k: V r i c ~ c .J. Org:aiioiiii,/ C / w i i i . 1976. 116. 1.
I). Stdlks. .I O r , q i i i i i ~ i i i e ~('/wiii.
/.
1991. 4/R. 127: h) S. Freitap. W,
K o l o d / i q s k i . t'. P:iuer. D. Stalks. .I. C/iiwi. S i c . Deiltiiii 7 r m \ . 1993. 3479.
[lo] A . .I. kdMiird% M A Pa\er, P. R . Raithhy. M.-A Rennie. C . A. Russell, D. S.
Wright. Aiiwii C ' l i v i i i . 1994. 106, 1334: Airgrii~.C ' l i c w i . h i . E d Eii,yI. 1994. 33.
1277
[ II] ('iystiil d;it,i l o r 2 C . , 2 t ~ z - N 3 L i 2 T2.I
e . = 354.85. orthoihomhic. space gi-oup
Piiijiu (no. 0 2 ) . ii = lLl38ll(3], /I = 1?.i51(4). <' =10.341(2) A. I/ = 351711) A'.
- 1 . 3 6 6 g c m ~ ' . F((1I)l))=1448. i.
= 0.71069A. T = 2 2 0 ( 1 ) K .
/ i ( M o k , l = 16.79 ciii- I . Data Mere collected 011 a Rigaku AFC6S diffractomeICI- oii ii c o l ~ ~ rprism
l ~ ~ (0.45
s
x 0.30 x 0.28 mm) mounted in a glass capillark h)
thi. c J - X i n c t h d Of a total 3533 collected reflections. 2040 \\ere ohserbed
I/ 4 . O O r i ( / ) ] . rlic structure w'as s o h e d hv direct methods (SAPI91. Fan Hail ; ~ . K i g A i i C oi-r.. Tokyo. 1991) and expanded using Fourier t~chiiiqiies
( D I K D I F ' J ~ Il'hc c1;ita were corrected for absorption. L o r c n v and polariz:ition cSl;.ct\. Nm-hqdropeii atonir were i-elined anisotropically. One of the
lilhiuiii a t m i \ w i i s disordcrcd over two sites (Li(3a) and Li(3h)) with equal
p c ~ p i i l n t i o i i r . Hydrogen atoms were included hut not refined. Refinement by
l~ull-m;itrixlea\t-squ:ires calculations converged a t R = 0.036 and K,,= 0.036.
411 c:ilciiliition\ for 2. 3, and 4 werc performed by using the teXsan cr>stlallographic package (Molecular Structure Corp.) See alw [IYh]
1121 A. A Dan~ipoulos.G. Wilkinson. B. Huswin, M. B. Hursthouse. J. C/iuii, Sot..
(%i,iii.
( b i i i i i i i i i i . 19x9. X96.
1131 . I ) 1 Mtiiixiihci-~.H W. Roesky. M Noitemeyer, S. Besser. R. Hcrbst-lrmer.
/. V c i / i i r / o r w l i 5 IYY3. 4Xh. 199: b ) H. W Roesky. J. Munzenbcrg. R . Bohra.
hl Noltenieyel-. J Ur,qiiioni<,/. ('hl'ii?. 1991, 41N. 339,
ler-Becker in 7 ' 1 ~( . / i f w i i s / r > ( I / /iio,~miieRiiig LT>,\mii,\(Ed.:
vier. Amsterdam. 1992. p. 132.
Ruhlandt-Senge. P. P Power. .Aiigcw C'/I~VII. 1994. 106. 35:
.Aiivm. C h i ? . /iir Ed. EiigI 1994. 33. 356: h) C. E. Housecroft. ('Iu\rw
,llo/rt.ii/c.c iil i h pB hi (A E / w w i i / s . Oxford Uiiiversity Press. Oxford. 1994. p.
24
1161 ti. Circgoi). P von R. Schleycr. R . Snaith. A d v . Iiiorg C/wiii. 1991. 37. 58.
[I71 ('ir>stiiI J a t ~liir 3 C,,,H,,N,P,Te.
.if =770.49. monoclinic. space group c'2.c
(110
15). t i
26.5YX(J). h = 9.195(1). ( = 17.79913) A. /I =109.?4(1 j .
I = 4 I l i 9 ~ 1 1 A '%
. = 4 . / i ~ . , , ~ , ~ = l , 2 4 5 g c F(000)=1616.
m-~,
j.=0.71069.&.
I = ? % ( I ) K. {i(MokZ)= 8.32cin - ' . Data were collected on an orange plate
(0.40 x 0.45 < ( I07 min) inouiitcd in ii gl;iss capillary O f a total 3975 collected
rcllectinns. 3043 \ x r e observed [ I > 3 110c(/)]. The structure wds solved by
&I-ect inethhcl\ (SAI'IYI) and expanded by using Fourier techniques. The data
ueie corrected i o r iihjurption. Lorentr and poldri7;ition effects. Non-hydrogen
atoin\ \cel-c rclincd ;inisotropicallq Hydrogen atoms were included hut not
relined. Relincment by full-matrix least-squares calculations converged ;it
K = 0 0-14 .ind R,, = 0.043. See also [l9h]
[ I X ] H -.I.K0ch. t ~ U:
. Roesky. S. Beser. R. Herhst-lrmer. C / i e i i i . Bi?. 1993. 126.
7
Nucleophilic Attack on (n-Allyl)palladium
Complexes: Direction of the Attack to the
Central or Terminal Carbon Atom by
Ligand Control""
A n a M. Castaiio, Attila Aranyos. Krilmrin J. Szabo,
and Jan-E. Bickvall*
Nucleophilic addition to (rc-allyl)palladium complexes is an
important step in a number of synthetically useful pall ad'iumcatalyzed reactions." for example, allylic nucleophilic substitutions."] allylic a c e t o ~ y l a t i o n . and
[ ~ ~ 1,4-oxidation of conjugated
diene~.'~
In' all these reactions the regiochemistry observed has
been attack at either terminus (C1 or C3) of the rc-ally1 group.
However, some time ago Hegedus reported an example of
attack at the central carbon (C2).[51and since then several
examples of such unusual reactivity have been reported with
(rc-ally1)palladium
Recently for a number of other
(rr-ally1)metal complexes attack at the central carbon has also
been observed,['~*I sometimes in a reversible reaction.['h. *I
Until now it has generally been assumed that only less stabilized carbon nucleophiles (pK, 20-30) are able to attack the
central carbon in (rc-allyl)palladium complexes.['. In this communication we provide evidence that also more stabilized carbon nucleophiles (pK, 14- 15), such as diethyl methylmalonate,
attack at the central carbon under certain conditions. We have
studied the factors governing the regiochemistry of the attack
(at the central or the terminal carbon) and explain the observed
regiochemistry.
The (rc-al1yl)palladium complex la, prepared in 90% yield by
reaction of2,3-dichloropropene with 1 equiv of PdCI, in the presence of C0,I9]was used as a substrate to study the effect of the
ligand and other parameters in the regiochemistry of the nucleophilic attack.["] Complex l a was allowed to react with sodium
diethyl methylmalonate (2.0-2.5 equiv) in THF at 78 ' C in the
presence of different ligands (2-6equiv) and left to warm up
overnight to room temperature. Two products. the doubly alkylated product 3 and the monoalkylated product 4,were obtained
(Scheme I , Table 1).
~
CI
LI
d c i l r i for 4 (',,H,,BN,Te.
34 = 428.88, ortliorhomhic. \pace
P h e i itlo 61). 0=l'i.X45(2). h=17.799(2). < . = 1 1 . 6 5 6 ( 2 ) A . G =
41 I ? . I ( X J A'. / = 8. / J ~ . , , =~ ~1.384 g c n i - ' . f'(000)=1744. I = 0 7106') A.
1 ' = 150 K. / i ( M o K J = 14.48 c111C'. Dat'i were collected on ii coIorless plate
( 0 . 5 5 x 0.10x I).17 min) mounted on a glass fiber. O f a total o f 5280 collected
rellection\. 26.74 wcrs o b s e n e d [ / > 3,00c(/)].
T h e structure was solved by the
hca\j ;itom method (PATTY) and expanded by using Fourier techniques. The
d a l , i \ccic c c m x t e d lor absorption. Lorentz a n d polariaition effects. Non-h)dropen atoin\ wcre refined anisotropicnll) Hydrogen atoms were mcluded but
1101 I-dined Kslinemcnt hy Ihli-iiintrix kist-squares Calculations converged at
K = 0.051 t i n e 1 K., = 0.055. h j Further dctailc of the crystal structure investigal i i i i i s 01'2 4 mciy be ohtained from T h e Director ol'the Cambridge Crystallographic D a t . ~('entre. 12 Union Road. C a n i h r ~ d g eCB2 1EZ ( U K ) . o n quoting
llie 11111loiii-iiiil citation.
.
edition. Clarendon Press, Ox[20] A E Well.;. . S i r w r i m i l I i i o r ~ y m ic~' / i w i F \ / r , ~ ,5th
loi-J. 1984. p. Il)h2
Mc( ~irlli!. X Zhang. M. G Kanalzidis. / i i ~ r , q (. ' h i ! 1993. 32. 2944:
.harig. M G K:inatzidis. J h i . C ' l i w i . S i x . 19Y4 //6. 1890.c) X. Zhang.
K ~ i i i ~ t ~Iiiorg.
d i ~ . Clioii 1994. 33. 1238.
[tF]
L'
L0
2
3
4
Scheme 1 . Reaction
E = CO,Et.
[*I
[**I
of complex
I
\\ith sodiiim dicth>l inetIiyIm;ilon;ite.
Prof. Dr. J:E. Bickvall. Dr. A. M Castario. A Ar;in!o\. D r . ti. _). SrahO
Department of Organic Chemistry. Univcrsit). of Upp\;il,i
Box 531. S-75121 Uppsala (Sweden)
Telefax: Int. code + (18)508542
e-mail: Jeb>[ikemi.uu.se
Fin;incial support from the Swedish Natural Science Kcsearch Council. the
Spanish Ministerio de Educacihn 5 Ciencia (fellow\hip to A . M . C'.). ; i d the
National Superconiputcr Contre i i i Sweden is gratefully xknowledgcd.
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Table 1 Product distribution iii the reaction of sodium diethyl methylnialonate
uirh 21 series of ally1 complexes 1 containing different lipands L [a].
Entry
L (equiv)
3 : 4 [b]
< 2 . >98
13.87
<1:>9Y
<1:>99
25.75
23 77
tions on 6 show that: 1) The orbital energies of the two lowest
unoccupied MOs, pa.and pa..,(Fig. 1) are rather similar and
vary for different ligands.['sJ 2) With NH, as ligand 'pa.is the
LUMO and approximately 0.4 eV below pa...3) With PH, as
ligand the order is reversed, and pa..has the lowest energy,
although the energy difference between the two orbitals is small
( < 0.2 eV) and perhaps not significant.
~
10.90
>YY:<1
>YY: < 1
[a] Unless otherwise stated, the ligind was added to a solution of I
i n T H F at
- 7 8 ' C . followed by addition of sodium diethyl methylmalonate in T H E The
reaction was allowed to warm to room temperature wemight. Conversion of
1 to products 3 andlor 4 was >95%. Abbreviations' dppf = 1.1'-bis(dipheny1phosphino)ferrocene: dppe = 1 ,?-bis(dipheny1phosphino)ethanc;dppb = 1.4-his(diphenylp1iosphino)butme: bpy = 2,T-hipyridine: tmeda = N,N,N'.N'-tetramethylethylenediamine. [b] Ratio determined by ' H N M R spectroscopy. [c] After
adding the ligand, the cold bath was removed for a few minutes to facilitate the
ligatid exchange. [d] Variable amounts of diethyl (allyl)methylmalondteand diethyl
2-(2-propenyl)meth~lmalonat~
were also obtained
Compound 3 is formed in a multistep process: addition of
the nucleophile to the central carbon of the (71-ally1)palladium
complex followed by elimination of C1- gives the substituted
(n-allyl)palladium complex 2, which subsequently undergoes a
second nucleophilic attack at the terminal carbon atom.['
Compound 4 is formed in a one-step attack by the nucleophile
at the terminal carbon atom.
The ratio between products 3 and 4 is strongly dependent on
the choice of the ligand (Table 1). 71-Acceptor phosphorus ligands favor terminal attack, whereas strong o-donor nitrogen
ligands favor C2 attack. Thus, the use of triphenylphosphane as
ligand afforded 4 highly selectively ( > 98 %j, indicating terminal attack by the nucleophile (entry 1). With the more electrondonating tributylphosphane some C2 attack took place. the ratio of 3 to 4 being 13:87 (entry 2). Interestingly, the bidentate
phosphane ligand dppe gave significant amounts of C2 attack
(entries 5 and 6). With bipyridine and tmeda as ligand only
product 3 from initial C2 attack was observed (entries 8-9).
Reaction of la with an even more stabilized carbon nucleophile, sodium methyl methylacetoacetate. afforded product 5 by
terminal attack even if tmeda was used as a ligand [Eq. (a)].
F'
la
5
To gain further insight into the mechanism of this reaction, a b
initio'"' calculations at the Hartree-Fock level as well as at the
second and fourth order Msller-Plesset perturbation theory"
were performed on (n-ally1)palladium complex 6, which contains simple phosphorus and nitrogen
A
ligands. Previous theoretical studies
L = PH3, NH3
on C2 attack by nucleophiles on (71L/pQL
al1yl)palladium
complexes have em6
ployed Extended Huckel MO (EHMO) calculations.[7b,1J1From results one of the studies,r141
frontier orbital controlled nucleophilic attack at the central carbon atom was considered unlikely, whereas in the other
study[7h1it was argued to be a possible pathway. Our calcula-
CP a'
CP a"
Fig. 1 . Possible LUMOs in Pd(x-allyl) complexes.
There are two possible explanations for the ligand effects
observed (Table 1): 1) There is a balance between charge controlled and orbital controlled reactions. 2) The reaction is frontier orbital controlled for all ligands, but the LUMO is different
for different ligands (pa.or cp,..). According to the first explanation, an electron-accepting ligand such as triphenylphosphane
would create significant carbenium ion character at the allyl
moiety. The complex can be best described as an allyl cation
coordinated to Pd', and therefore the positive charge in the allyl
group is located more on the terminal carbon atoms. As a result,
charge controlled attack at the terminal carbon would be favored. On the other hand, with more strongly electron-donating
ligands such as tmeda, the positive charge will be smaller and
frontier orbital control will become more important. When cp,.,
where the MO coefficient is large at the C2 carbon, is the
LUMO, attack at this carbon will predominate. The fact that
the methyl methylacetoacetate anion [Eq. (a)], which is more
stabilized than the dialkyl methylmalonate anion, gives terminal
attack in a reaction with the allylpalladium complex containing
tmeda as ligand is consistent with the first explanation. The
energy of the nucleophile orbital (HOMO) will be significantly
lower in this case and therefore the rate of the frontier orbital
controlled pathway, which is inversely dependent on the difference Et.UMO-EHOMOr
would decrease."61
On the other hand, if the reaction is completely governed by
frontier orbital control (as in the second explanation) the terminal attack on allylic complexes with PPh, and P(OPh), as ligands would be explained by a change of LUMO from p,. to pa..
on changing from the strong o-donor ligands to the 71-acceptor
phosphorus ligands. This is in agreement with the calculations.
However, the reason for terminal attack by sodium methyl
methylacetoacetate on 1 with tmeda as ligand [Eq. (a)] is not
obvious with this explanation, but may be rationalized by repulsive HOMO(nuc1eophile)- HOMO(ally1) interactions as suggested by Musco et al.[7h1
Recently, Murai et al.[7c1
showed that the nucleophile sodium
diethyl methylmalonate attacks the C2 carbon atom of a
(rr-al1yl)platinum intermediate corresponding to 1. The (n-allyl)platinum species was generated from 2-chloro-2-propenylacetate and [Pt(CH,=CH,)(PPh,),] in a catalytic reaction that
afforded 3 as final product.
In summary. we have demonstrated for the first time that
nucleophilic attack by a dialkyl malonate anion (a more stabilized carbon nucleophile) takes place at the central carbon atom
of a (71-allyl)palladium complex. The regiochemistry of the reac-
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tion is controlled by proper choice of ligand on the metal. The
effect of temperature, chelation, and other reaction parameters
are under investigation.
6,7-Bis(methoxycarbonyl)-2,3-dimethylIS]( 1,4)naphthalenophane,
the First Benzoannelated [S]Paracyclophane
Received: July 6. 1995 [Z81751E]
German version' AiiqJit. Ciiein. 1995. 107. 2167 -2769
Daniel S. van Es, Franciscus J. J. d e K a n t e r .
Willem H. de Wolf, and Friedrich Bickelhaupt*
Keywords: complexes with carbon ligands . ligand effects .
nucleophilic attack palladium compounds
[I]
Pii//iii/iiiiii iii Oi.,y(iiiii S)it~/ii>\i.\,
Sjnipi~uiii
8.'.
'IC.I, VkIll). ~ ' I J < i / I I ' N ' I ' / I > ? 1994. 51). 285-572.
in prini ,Vo. 52 (Ed.: J. E.
121 n) t oi- ii recent reriew, see: S. A. Godlesky in Coiftpr[,lif~ii.si~'
Orgmiic Si,ii//imi.\,
I?)/. 4 ( t d s . . B M rrost. 1. Fleming, M. F Semmelhack). Pergamon, Oxford.
1991. p 5 8 5 . h ) 1.M. Nilsson, P. G Andersson. J. E. Bickvall. J AIII. Clrmi.
So[ 1993. / /S. 6609. c) B. M . Trost. T. R. Verhoeven in Coi?i~'vlii,".\i~c,
~ ~ ~ ~ ~ l i i i J i i (./ir,i??f\ir,v,
f ~ ~ / ~ / / / i I+/.
~
N (Eds : G . Wilkinson. F G. A Stone. E A
Abel). Pergamon. Oxford. 1982. p 799; d ) J. Tsuji. Acc. Clwift Rrs. 1969. 2.
144.
13) a ) A . Heurnann. B Akermark. Aiigeir. Clitmi. 1984, Y6. 443: A i i g c ~ i 'Client. I n / .
) S . Hansson, A Heumann, T. Rein. B. Akermark.
5, c) J E. Biickvall. R B. Hopkins. H . Grennberg.
sthi, J. A n i . Clicm. Soc. 1990, 112. 5160.
14) a ) 1 k, Biick\'ill in Orgarionir/iiNic Rqqcntv in Orgimic .Yrii//ic,si\ (Eds.: J. H
Batewii. M 8. Vitchell). Academic Press. London. 1994. p. 81: b) J. E.
Backwll. .Ad1 .\lei Org. C / i m . 1989. I. 135, c) J. E Biickvall. J E. N y s t r h .
R F Nordbei-g, .I Ani C/fiwt Soc. 1985. 107. 3676: d ) A. M . Castafio. J. E.
Bickcall. h i d 1995. 117. 560.
[ S ] L S Hegedu,. W. H. Darlington. C. E. Russell. .I Org. U K W1980, 45. 5193
[ h ] :I) ti M R Hoffmann. A R. Otte. A Wilde. S. Menzer. D. J Williams.
.4ii,qi',,. C'/ii,ui 1995. 1/17. 73, Aitgeit'. Chmi. f i t ( . E d Eitgl. 1995. 34. 100. b) A.
Wilde. A R Otle. H. M. R. Hoffmann, J Clwii. Sot.. C/irwi. C i ~ t i i i i i i i n .1993.
615: c ) H M R Hoffmanu. A. R. Otte. A. Wilde. Aizgcnr C/iciit. 1992. 104.
2 3 : Aii,ycii~Cliciii. I n / . Ed. Enx/. 1992. 32. 234; d) C . Carftigna. L. Mariani. A.
Mu\co. ( i S'illese. R. Santi, J Org Clierii. 1991. 56. 3924; e) C. Carfagna. R.
GxLirini, A Musco. .I Mid. Ciiriil. 1992. 72. 19.
17) For ii recent reiieW on rnstall;icyclobut;ine complexes of group 8 transition
nietds. w e ' I ) I' W Jennings. L L. Johnson. C/iiwt. Rev 1994. Y4. 2241 : b) C.
(.iirIqii:i. it. Galarini. K. Linn. J.A. L6per. C. Mealli. A Musco.
( ~ i ~ , ~ ~ i i i , ~ i i i ~1993.
, i ~ i / / 12.
i ~ ~ 3019:
\
c ) K. Ohe. H . Matsuda. T Morimoto. S.
Ososhi. N <'h,it:ini, S Mural. J. A m C/imi So<..1994, 116, 4125: d) M.
l q ~ l i r i t i k h i n e . X I . 1. H. Green. R. E MacKenrie, J Climi. Sot.. Clicmi. Cotw
iiiiiii 1976. 610. c ) M Ephritikhine. B. K. Francis. M. L. H. Green, K. E .
M:icKenne. M J. Smith. .I C h i S i r . Drdion 77mi.s 1977. 1 1 x 1 : 1') E. B.
Tpiden~G I ("isty. J M . Stryker. .I A m Clion Soc. 1993. 115, 9814.
[XI a ) t B r.i:iclen. J. M. Stryker. J A i i f C / I P I ISIo. ( . 1990. f 1 2 . 6420: b) G . J. A .
Ad;im. S ( I . ll;i\ie\. K . A Ford, M. Ephritikhine, P. F. Todd. M. L. H.
Green. .I , U d ( ~ i i / i i / .1980. 8. 15: c) Ref. [7 b].
[9) f'. R . .4ubiiin. P B. MacKenzie. B. Bosnich. J hi C/im?i.So( 1985. 107.
The chemistry of small strained cyclophanes keeps fascinating
chemists, both because of the remarkable physical and chemical
properties of these compounds and because of the challenge
posed by their synthesis."] In 1985. we reported the first synthesis of [5]paracyclophane, which was at that time the smallest
In contrast to its ncxt higher hoknown [n]paracycl~phane.[~~
mologue [6]para~yclophane,[~]
[5]paracyclophanc is not stable
at room temperature; it could only be stored in dilute solution
at low temperatures."' Introduction of substituents at the benzene ring slightly increased the thermal stability."l Therefore, a
further increase in stability could be expected on annelation of
an additional benzene ring, especially since Tobe and co-workers had shown that [6](1,4)naphthalenophane is more stable
than [6]paracy~lophane.[~~
Here we report the synthesis and
characterization of a derivative of [5](1,4)naphthalenophane,
which is the smallest known [n](1,4)naphthalenophane and the
first benzoannelated [5]paracyclophane.
The Dewar benzene 114'] was converted by known methods,16.71 as indicated in Scheme 1, via the corresponding diol
___)
1) DlBAHlBuLi
(CHh
COOMe
(
C
H
S
\
2) PBr,
3) Zn
1
2
-
2
n
COOMe
(cH2)5
DDQ
__t
4
COOMe
207.3.
[ 101 Kccentl), kl w
i i
3
et al. generated homologous (n-a1lyl)palladium and -platinum
coinplexch i n vtu in catalytic reactions from 2-chloro-2-propenylacetatesto
stud? the SIC o f nucleophilic attack [7cj
[ I I ] Cornpie\ I 15 indeed highly reactive m d reacts even at - 7X C with stabilized
ciirhon nuclcophiles
in GAUSSIAN 91 was employed. Poi- hydrogens the primitive
w;is used contracted to [?s] For carbon. nitrogen. and chlorine
;itom\ the 195.5p) basis of Huzinaga [I2b] was used. augmented with one
d-lunction i i n d contracted to [3s&ld]; the chlorine core was replaced by an
rffccti\cci~rupotential (ECP) [IZc]. For p;illadium a relativistic ECPaccording
to ILiy .ind M ~ d [t I l l was used. The 4s and 4p orbitals are described bq :I
~ n g l /ct:i
t ~ a m t r x t i o n . the ralence Ss and 5p orbitals by a double Letii basis,
and the 4d orbital by a triple zeta basis including one diffuse d-function. h)
S tiii/~nng.i..l Chnii. Plri,.~1965.42, 1393.c) P. J Hay, W K. Wadt. /hit/ 1985,
82. 170. d l 1). 1. Hay. W. R. Wadt. i / d . 1985, 82. 299.
[I31 I' < ~ H'irihxan.
.
J. A Pople. T l i w r Cliim. A[(a 1973. 28, 213.
[14) M . D Curti&.0. Eiaenstein. Orguirni?tt,rol/i~.\1984. 3. 887.
o1'EHMO results (based on the experimental geometrq) Formica
led thal these two orbitals are similar i i i energy and i-everse their
irin. M Formica. A Musco. R. Pontellini. K . Linn. C.Mealli. .L
01 ~ ~ I i i ( J i l l ~ <' 1' / i ~ V J i 1993. 448. Ch.
[Ib) ii) G . Kinpinan. .I . 4 i ~ i .C h c n f . S o l . 1968, 90, 2 : b) C/iiwii[ii/ Rrwi,rii.iri.I n i d
R w iiiiii I'iiilr!, (Ed. G. Klopman), Wiley. New York. 1974; c) 1. Fleming,
f i < t t i / w i - Ofh i i d s mid Orgoiik R c r t ~ ~ r i o Wiley.
i ~ . ~ . Neu, York. 1978.
n
COOMe
(cH2)5
II
1
COOMe
\COOMe
4
5
Scheme 1. SSnthesis of 5 from 1. DIBAH
=
Diisobutylaloniinum hydride.
(step 1) and dibromide (step 2) to the triene 2 (step 3 ) . In a
Diels-Alder reaction with dimethyl acetylenedicarboxylate
(DMAD), 2 yielded the adduct 3. which in turn was oxidized
with dichlorodicyanobenzoquinone (DDQ) to give 4. After
preparative thin layer chromatography, 4 was obtained in low
yield, but pure.
Initial attempts to aromatize 4 photochemically to the naphthalenophane 5 with a white light source resulted in the forma[*] Prof. Dr. F. Bickelhaupt. Drs. D. S. van E?, Dr t. J. J. de Kanter
Dr. W. H. de Wolf
Scheikundig Laboratoriurn. Vrije Universiteit
De Boelelaan 1083. NL-1081 H V Amsterdam (The Nethei-lands)
Telefiix. Int. code (?0)4447488
+
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ally, central, palladium, directional, atom, attack, terminal, complexes, carbon, ligand, nucleophilic, control
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