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Assistance by Electrophiles in Photoinduced AlkylidyneЦCarbonyl Coupling.

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[ 2 ] Y Aoydma, Y Tanaka, S. Sugahara, J. Am. Chem. Sac. 1989, lfl, 53975404; R. P. Bonar-Law, A. P. Davis, B. A. Murray, Angew. Chem. 1990,
102. 1497-1498; Angeu. Chem. Znt. Ed. Engl. 1990,29. 1407-1408.
[3] M . L. Bender, M. Komiyama, Cyrlodextrin Chemistry, Springer, Berlin,
1977; W. Saenger, Angew. Chem. 1980,92,343-361; Angen. Chem. fnt. Ed.
Engl. 1980.19. 344-362; R. Breslow, Arc. Chem. Res. 1980, 13.170-177;
I. Tabushi, ihid. 1982, 15, 66-72.
[4] I . Tabushi, N. Shimizu, T. Sugimoto, M. Shiozuka, K. Yamamura, J. Am.
C h m . Soc. 1977, 99, 7100-7102; J. Franke, F. Me n, H. W. Lorensky,
W. M. Muller. W. Werner, F. Vogtle, J. Inclusion Phenom. 1985,3,471-478:
G. C . Catena, F. V. Bright, Anul. Chem. 1989,61,905-909; H.-J. Schneider,
T. Blatter. S. Simova, J Am. Chem. SOC.1991, 113, 1996-2000.
[S] Y. Matsui, K. Mochida, Bull. Chem. Soc. Jpn. 1979, 52, 2808-2814.
[6] K. A. Connors. Binding Constunts, Wiley-Interscience, New York, 1987,
pp. 175-183.
[7] M. Janado, Y Yano, J Solution Chem. 1985,14,891-902; K. Miyajima, K.
Machida, M. Nakagaki, Bull. Chem. Soc. Jpn. 1985, 58, 2595-2599.
[S] Pis the partition coefficient of an alcohol in the diethyl ether/water sytem;
for 6,P z 0.
[9] S. J. Angyal, V. A. Pickles. Ausr. J. Chent. 1972, 25, 1695-1710.
Assistance by Electrophiles in Photoinduced
Alkylidyne-Carbonyl Coupling **
Irradiation of the alkylidyne carbonyltungsten complexes
cis-la, b with visible light in the presence of electrophiles ECl
affords the alkyne complexes trans-2a -e.[" 81 The reactions
are accompanied by the photochemical cis-trans isomerization of complexes LL9]Thus, the same results are obtained
when the trans isomers of complexes 1 are used as the starting materials. In the absence of light, either no reaction or a
different outcome is observed under otherwise similar conditions. The reaction of trans-la with HCl was previously reported to give the alk ylidene complex trans-w(CHPh)C1,(CO)(PMe3)2][91.
la: R = M e
2a: R=Me, E = H
2b: R = Me, E = C(O)CMe3
2C: R = Me, E = C(O)C6H4-4-OMe
2d: R =Ph, E = C(O)CMe3
2e: R = Me, E = Si(CMe3)aPh
Ib: R = Ph
By Andreas Mayr,* Cecilia M . Bastos, Richard 7: Chang,
John X . Haberman, Katrina S. Robinson,
and Deirdre A . Belle-Oudry
Dedicated to Professor Wolfgang Beck
on the occasion of his 60th birthday
The coupling of alkylidyne and carbonyl ligands may be
induced in different ways."] In most reactions, including the
first example discovered by Kreissl et al.,[*] alkylidyne-carbony1 coupling is induced by the addition of a strongly
nucleophilic ligand to the metal center. There is some indication that the coupling of alkylidyne and carbonyl ligands
may also be induced by electrophiles. Schrock et al.[31reported that the reaction of [W(CH)Cl(PMe,),] with CO in the
presence of aluminum reagents such as (AlC13)2gives [W(y2HCCOA1CI3)C1(CO)(PMe,),1. Lippard et aLL4]demonstrated the formation of disiloxyalkyne ligands upon reaction of
the siloxymethylidyne complex [Ta{COSi(iPr),}(CO)(dmpe),1
[dmpe = bis(dimethylphosphinoethane)] with silylating
agents. Related alkyne ligands of the type RCCOE (E =
electrophile) are easily accessible by the addition of electrophiles to q2-ketenyl ligands obtained by nucleophileinduced alkylidyne-carbonyl coupling.[51Geoffroy et aLf6I
were able to demonstrate that ketenyl complexes may also be
generated by irradiation of alkylidyne carbonylmetal complexes in the presence of nucleophiles. It was proposed that
the role of the nucleophile was that of trapping a photochemically generated ketenyl metal complex. The possibility that
some alkylidyne-carbonyl coupling reactions may be induced by electrophiles, and the well-established reactivity of
y2-ketenyl ligands towards electrophiles, suggested that electrophiles may also be effective in assisting the photoinduced
process. Here we report that in photoinduced alkylidynecarbonyl coupling reactions electrophiles are effective
reagents for trapping the coupling products.
Complexes 2a-e belong to a well-established group of
metal complexes with four-electron-donor alkyne ligands["]
and were characterized by spectroscopic methods." 'I In the
'H NMR spectra the virtual triplets for the phosphine
methyl groups indicate the mutual trans arrangement of the
phosphine ligands.['2] In the I3C NMR spectra the alkyne
ligands give rise to two resonances between 6 = 190 and 230,
chemical shifts characteristic of four-electron-donor alkyne
ligands.["] The carbonyl ligand of complexes 2b-e gives rise
to a single absorption in the IR spectrum. In dichloromethane solution complex 2a exhibits two IR absorptions at
1925 and 1940 cm- indicating the presence of two isomers;
however, in the solid-state spectrum (KBr) only one CO
absorption is found.
'
Fig. 1. Crystal structure of2a. Selected bond lengths [A] and angles ["I: W1-C7
2.05(1). W1-C8 1.97(1), Wl-Cl5 2.01(1), Wl-PI 2.511(3), W1-P2 2.512(3), W1CI1 2.528(3), Wl-Cl2 2.454(3), C7-C8 1.32(1); Cl-C7-C8 135(1), C7-(28-02
136( 1).
[*I Prof. A. Mayr,* Dr. C. M . Bastos, R. T. Chang, J. X. Haberman,
["I
K. S . Robinson. D. A. Belle-Oudry
Department of Chemistry
State University of New York at Stony Brook
Stony Brook, NY 11794-3400 (USA)
We thank John D. Franolic, Raju Subramanian, and Prof. Stephen A.
Koch for the X-ray crystallographic studies. This work was supported by
the Petroleum Research Fund administered by the American Chemical
Society, and by the National Science Foundation.
Angen'. Chem. Int. Ed. EngI. 31 (1992) No. 6
0 ITCH
The solid-state structures of the ynol complex 2a (Fig. 1)
and of the alkynyl ester complex 2c (Fig. 2) were determined
by X-ray crystallography.[' 31 The structural parameters
(Table 1) are not unusual, but the orientation of the ynol
2a is Opposite to that expected. In
k a n d in
plexes of the type [WX,(alkyne)(CO)L,] the alkyne ligands
Verlagsgesell.~chufimhH, W-6940 Wernheim, 1992
0570-0833/92{0606-0747$3.50 f .25/U
141
C1141
c (91
Fig. 2. Crystal structure of 2c. Selected bond lengths [A] and angles [ I : Wl-C7
2.03(1), W1-C8 1.99(1), Wl-Cl5 1.96(1),W1-PI 2.507(4), Wl-P22.522(4), W1CI1 2 518(3), Wl-Cl2 2.479(3), C7-C8 1.28(1), CI-C7-C8 137(1), C7-C8-02
135(1).
prefer the orientation parallel to the W-CO axis for electronic reasons."'] Alkyne ligands of the type RCCOR are expected to prefer the orientation with the oxygen-substituted
carbon atom proximal to the carbonyl ligand (A).[141This
situation is found in the solid-state structure of the
alkynylester complex 2c. In the ynol complex 2a the oxygensubstituted end of the alkyne ligand is oriented distal to the
carbonyl ligand (B). This electronically less stable orientation is presumably stabilized by a hydrogen bond between
the OH group of the ynol ligand and the chloro ligand CI 1.
Even though the OH hydrogen atom was not found in the
X-ray structure analysis, the 0 2 - C l l distance of 3.022(9) A
is suitable for a hydrogen bond.['51 The presence of two
v(C0) frequencies in the IR spectrum of 2a in solution indicates that the hydrogen bond between the OH group and the
chloro ligand stabilizes the electronically less favorable orientation B to such an extent that both conformers A and B
are present in comparable amounts in solution.
A
B
In two other structurally characterized ynol tungsten complexes 3'16]and 411']the OH group is stabilized by hydrogen
bonding to cocrystallized donor solvent molecules, whereby
the ynol ligand in 4 also adopts the electronically less favorable orientation. The synthesis of 3 by irradiation of 5 in
[W(acdc)CI(PhCCOH)(CO),] . OEtz 3
[W($-C5H5)(Me-4-C,H,CCOH)(CO)(PMe,)][BF,]
.OCMez 4
[W(CPh)CI(CO),]
5
the presence of acetylacetone was reported by Fischer and
Friedrich.['61 It is now recognized as the first example of
photoinduced alkylidyne-carbonyl coupling.[61Based on the
748
C,
V C H Verlugsgesrilschuft nihH W-6940 Wernheim 1992
results reported here it appears that this reaction may also
represent the first example of an electrophile-assisted photoinduced alkylidyne<arbonyl coupling."' Formation of 3
could involve initial substitution of the chloro ligand and
one carbonyl ligand in 5 by acetylacetone, accompanied by
elimination of hydrogen chloride. The liberated HCI could
then trap a photochemically generated ketenyl complex to
give the final product.
The reaction of photochemically generated ketenyl ligands with electrophiles is an efficient method for the assembly of metal-coordinated ynols and alkyne derivatives, such
as alkynyl esters and alkynyl silylethers, from three components: alkylidyne ligand, carbonyl ligand, and electrophile.
This method may prove useful in the synthesis of such compounds. The reactions of organic alkynyl esters has been
investigated only in recent years,"8] and very little is known
about their coordination chemistry. Several complexes of
alkynyl esters were previously prepared by acylation of stable ketenyl metal complexes.[' 91
Experimental Procedure:
In a typical procedure, one equivalent of the electrophile was added to a solution of la, bin T H F at - 78 "C. (For the synthesis of 2a. slightly moist AICl,was
used as the source of HCI.) The mixture was irradiated from a distance of
10-20 cm with a regular 300 W projector lamp for approximately 2-3 h. During this time the color of the solution changed from light yellow to blue. Compounds 2a-e were purified by chromatography on silica gel at -30°C (10%
THF/CH,CI,for 2a. CH,CI, for 2b, and 2 % THF/CH,CI, for 2c-e) and recrystallization from CH,CL,/hexane (isolated yields: 80% for 2a, 68 % for 2b, 77%
for 2c, and 51 % for 2d). Complex 2e is obtained in 20% yield in only about
80% purity.
Received: December 20, 1991 [Z 5086 IE]
German version: Angeu. Chem. 1992, 104. 802
CAS Registry numbers:
l a , 107133-58-4; 1b, 140903-07-7: 2a. 140926-02-9; 2b, 140903-08-8; 2c,
140903-09-9; 2d. 140903-10-2, 2e, 140903-11-3: CIC(O)CMe,, 3282-30-2:
CIC(O)C6H,-4-OMe, 100-07-2; CISi(CMe,),Ph, 140903-06-6.
[ I ] A. Mayr. C. M. Bastos. Prog. h o g . Chem., in press.
[2] F. R. Kreissl, A. Frank, U. Schubert, T. L. Lindner, G. Huttner. AnKew.
Chen?. 1976, 88, 649: Angew. Chrm. I n / . Ed. Engl. 1976, 15, 632.
[31 S. J. Holmes. R. R. Schrock, M. R. Churchill. H. J. Wasserman,
Orgunomeiullics 1984, 3. 476.
141 R. N. Vrtis, S . Liu. C. P. Rao, S. G. Bolt. S. J. Lippard. O r g n n o m e l u l h
1991. 10, 275.
[5] a) F. R. Kreissl, W. Sieber, M. Wolfgruher. Angew. C h e m 1983, 95, 503;
A n g w . Chem h i . Ed. Engl. 1983, 22. 493; Angiw. Chrm. Siippl. 1983. 631 :
h) Z. Narui:forsch. B 1983. 38. 1419.
161 J. B. Sheridan. D. B. Pourreau, G. L. Geoffroy, A. L. Rheingold, Organomerullics, 1988, 7. 289.
171 G. A. McDermott. A. M. Dorries, A. Mayr, Orgunomerullirs 1987,6,925.
[8] 1b: 1R (CH,CI,): C [cm-'1 = 2002 (s), 1930 (s) (CO).
[9] A. Mayr, M. A. Kjelsberg, K. S. Lee, M. F. Asaro, T. Hsieh, Orgunonzerullics 1987, 6. 2610.
(101 J. L. Templeton. Ads. Orgunopner. Chem. 1989, 29, 1.
[I 11 Characteristic spectroscopic data of the complexes 2a-e. 2 a : 'H NMR
(300MHr. CDCI,, 25°C. TMS): 6=1.36 (virt. t, J = 4 . 2 H r . 18H:
PMe,), 7.3- 7.8 (m, 5 H : Ph), 10.30 (hr, 1 H : OH); " C NMR (CDCI,,
25 T): 6 = 194.3 (PhCCO). 229.3 (PhCCO), 238.5 (CO); IR (KBr):
C [cm-'1 = 3250 (m.OH), 1941 (s, CO): (CH,CI,, 25 ' C ) : i. [cm-'1 =
l940,1925(CO). 2b: 'H NMR(300 MHz.CDCI,, 25"C.TMS): d =1.41
(virt.t,J=4.4Hz,18H;PMe,).1.45(s,9H;CMe,),7.40-8.14(m,5H,
Ph); ',C NMR (CDCI,, 2S"C): 6 =173.0 (C=O), 212.1 (PhCCO), 224.2
(PhCCO), 233.8 (t. J(P,C) = 6.2 H,I CO); IR (KBr): [cni-'1 =1945 (s,
CO). 1744 (m. C=O).
2c: 'H NMR (300 MHz, CDCI,. 25'C. TMS): 6 =1.43 (virt. t.
J = 4.3 Hz,18H: PMe,). 3.91 (s, 3 H ; MeO), 7.0- 8.3 ( m , 9 H ; Ph,C,H,);
" C N M R (CDCI,. 25°C): 6 =165.6 (C=O). 213.2 (PhCCO), 225.8 (t.
J(P,C) = 5 Hz: PhCCO), 233.4 (I. J(P,C) = 6 Hz; CO); IR (KBr):
[cm-'1 = 1954 (s. CO). 1742 (m. C=O).
2d: ' H NMR (300 MHz, CDCI,. 2 S T , TMS): 6 =1.18 (s, 9 H : CMe,),
1.63 (virt. t, J = 4.4 Hz, 6 H ; PMe,Ph), 1.85 (t. 'J(P,H) = 4.4 Hz. 6 H ;
PMe,Ph). 7.1-7.6 (m, 15H; Ph, C,H,); ' T N M R (CDCI,. 2 5 - C ) :
6 =171.9 (C=O). 213.3 (t, J(P,C) = 4.5 Hz; PhCCO). 223.3 (t. J(C.P) =
4.5 Hz: PhCCO), 233.2 (t, J(P,C) = 6.0 Hz; CO); IR (CH,Cl,):
P [cm-'1 =1945 (s. CO), 1744 (m. C=O).
0570-0~333319210606-0748
$ 3 SO+ 25.(10
Angebt Chem Inr Ed Engl 31 (1992) N o 6
Z e : ' H NMR (300 MHz. CDCI,. 25 C. TMS): 6 =1.22 (s, 9 H ; CMe,),
1.40 (virt. t. J = 4.3 Hz, 1 8 H ; PMe,). 6.9-7.8 (m. 15H; Ph, SiPh,);
"C NMR (CDCI,, 25 "C): 6 = 211.9 (PhCCO), 225.3 (PhCCO), 233.3
(CO): 1R (CH,CI,): ? [cm-'1 =I943 (s. CO), 1649 (w, CCO).
(121 J. M. Jenkins. B. 1 . Shaw, J. Chum. Suc. / A ) 1966. 1407.
113) Crystallographic data for Za and 2c. 2 a : C,,H,,CI,O,P,W, M = 553.06,
P2,;/7(No. 14), N = 8.668(2), b = 25.76(1), c = 9.541(4) A.8 =102.79(4)".
V = 2078(3)
Z = 4. pcAlcd
= 1.768 gcm-3. ;i(MoK,) = 60.93 cm-'.
1533 unique observed reflections. 3 ' < 2 8 < 47.9-, R = 0.029, R, =
M = 687.19. PcrrZ,(No. 29). u =15.584(1),
0.037. 2 c : C,,H,,CI,O,P,W,
h =12.599(1). r =13.962(1)A, fl=90.0', V = 2741.3(1)A3, Z = 4 ,
pEalcd
=1.665 gem-', p(Mo,,) = 46.40 em-', 2206 unique observed reflections. 3" < 2 8 < 60". R = 0.035. R, = 0.034. All intensity measurements were made at room temperature, using Mo,, radiation (graphite
monochromator, 2. = 0.71069 A), and a variable-rate, 0-20 scan technique. Empirical absorption corrections were applied. The structures were
solved by conventional heavy-atom methods and refined by the full-matrix
least-squares method. All calculations were performed using the TEXRAY
programs. For 2c, both enantiomers were examined. Further details of the
crystal structure investigations can be obtained from the Fachinformationszentrum Karlsruhe, GeSelkChdft fur wissenschaftlich-technische Information mbH. D-W-7514 Eggenstein-Leopoldshafen 2 (FRG), by quoting the depository number CSD-56078. the names of the authors, and the
journal citation.
1141 a) D.C. Brower. K. R. Birdwhistell, J. L. Templeton. OrgunomefallicJ
1986. 5. 94; b) W. J. Sieber, M. Wolfgruber. N . H. Tran-Huy, H. R.
Schmidt, H. Heiss. P. Hofniann, F. R. Kreissl. J. Orgumme/. Chrm. 1988,
340. 341
(151 D. Mootz, J. Hocken, A n p i , . Cliem. 1989. 101, 1713: A n g w . Chem. Int.
Ed. Engl. 1989. 28, 1697.
[16] E . 0. Fischer. P. Friedrich, A n g r x Chem. 1979, 91, 345; Angew. Chem.
Int. Ed. Engl. 1979. 18, 327.
[17] J. A. K. Howard, J. C. Jeffery, J. C. V. Laurie, I. Moore, E G. A. Stone, A.
Stringer, Inorg. Chin?.Arfu 1985, 100, 23.
[18] P. J. Stang, M. Boehshar, H. Wingert, T. Kitamura, J. Am. Chem. SOC.
1988, 110, 3272.
1191 K. A . Belsky. M. F. Asaro. S . Y. Chen. A. Mayr. Organometullics, in press.
CDCI, is consistent with the apparently unique bis(viny1hydrazone) structure shown in 1a rather than the expected
bis(azine) tautomer 1 b. The resonance of the vinyl protons is
observed at 6 = 6.0, and the downfield shift of the internal
NH protons (6 = 3 4.3) Is consistent with their intramolecular
hydrogen bonding to the transannular pyridine nitrogen
atoms. Addition of trifluoroacetic acid to the CDCI, solution apparently gives 1 . 2H' since the vinyl proton resonances are no longer observed and the acidic protons give a
broad resonance centered at 6 = 19. As suggested by the
presence of enamine moieties in structure 1 a, DDQ selectively aromatizes two rings of 1 to give bis(ary1hydrazone)
macrocycle 4, which still possesses two internal hydrogens
(6 = 17.6).
Q&jfk
Ion-Selective Hydrazone-Azine Tautomerism of a
14-Membered Macrocylic Ligand **
By Thomas W Bell* and Andrew 7: Papoulis
Bridged pyridine ligands,"' including torands,[21are versatile complexing agents for metal ions. In the course of
current efforts to incorporate pyrrole rings into torands using the Piloty rearrangement of a ~ i n e s , 'we
~ ] have discovered
a novel 14-membered azamacrocycle 1. The binding of lithium and the smaller alkaline-earth metal ions by this ligand
is accompanied by pronounced changes in its UVjVIS absorption characteristics. Ion-selective optical sensors based
on metal complexation are of current interest for analytical
application^.'^]
Macrocyclic ligand 1 was synthesized in two steps from
9-n-butyl-2,3,7,8-tetrahydro-l
H,6 H-acridine-4,s-dione 2['l
(Scheme 1). Slow addition of 2 to a large excess of hot
methanolic hydrazine gave (E,Z)-dihydrazone 3 as a yellow
precipitate. Condensation of diketone 2 with dihydrazone 3
in hot methanol gave macrocycle 1 as a yellow-orange solid
in 38-47 O h yield with most methods of addition of the reactants. However, when higher dilution was achieved by simultaneous, slow addition of 2 and 3 to hot methanol, 1 was
produced in 82% yield. The ' H N M R spectrum of 1 in
9
fi
tt"Mg2+#
f l H H'#
32
1 *2H'
lb
la
;
4
1 . Mg2+
Scheme 1. a:Hydrazine, MeOH ( 5 5 % ) ; b:MeOH (82%); c:Dichlorodicyanobenzoquinone (DDQ), toluene (63%); d:Mg(NO,), .6H,O, CH,CN (33%).
Macrocycles 1 and 4 both contain 14-membered rings with
four of the six nitrogen atoms in the correct positions to
coordinate metal ions. To do this 4 must either lose the
internal protons or tautomerize to the bis(azo) form, whereas I should readily form metal complexes by tautomerization
to the bis(azine) form 1b. Thus 1 reacts with Mg(NO,), in
CH,CN to form 1 Mg(NO,), , which was isolated as a yellow solid. FAB-MS, 'H NMR, 13C NMR, and FT-IR data
are in keeping with the C, symmetric structure. Apparently
1 . Mg(NO,), does not possess a horizontal mirror plane,
since two-proton multiplets are observed in the 'H NMR
spectrum at 6 = 2.8 and 3.3 displaying geminal coupling
( J = 17 Hz). This featuie suggests that 1 exists in a puckered
conformation in the complex, possibly due to axial coordination of Mg2+ by NO; on only one face. Ring methylene
1
[*] Prof. T. W. Bell, A. T. Papoulis
Department of Chemistry, State University of New York
Stony Brook, NY 11794-3400 (USA)
[**I
This work was supported by the National Institutes of Health (PHS grant
GM 32937). The 600 MHz spectrometer was purchased with funds from
the National Institutes of Health (RR05547A), the National Science
Foundation (CHE 891 1350), the Center for Blotechnology, and the State
University of New York, Stony Brook.
Angrw Chem. Int. Ed. Engl. 31 (1992) N o . 6
0 VCH VeriugsgrseN.sLhufi mhH. W-6940 Weinhrim, I992
0570-0833j92/0606-0749 $3.50+ ,2510
749
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