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Inductivity and Bridging in Ammonium and Carbenium Ions.

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slightly shorter than in 5. Two carbonyl ligands are staggered with respect to the ring atoms; the third carbonyl
group assumes a n almost eclipsed position relative to the
phosphorus atom. This conformation apparently corresponds to that with the least steric interactions between the
ring substituents and the carbonyl ligands, and rather resembles that in tricarbonyl(2-ethyl-4-methoxy-3-methyl-1n a p h t h o l ) c h r ~ m i u m , which
~ ' ~ ~ has a comparable substitution pattern. In the N-, P- and S-heterocyclic complexes
investigated so far,['*. I 4 l however, an approximate trans-arrangement of the ring heteroatoms to a carbonyl group was
observed.
In contrast to both 5 as well as to uncoordinated phosphininesl"] the heterocycle in 3a is slightly puckered
(largest torsion angles: C13-PI-Cl-C2 5.2(2)", Pl-Cl-C2C3 -5.8(4)", for numbering see Fig. 1); this puckering is
still found in the neighboring ring, whereas the third ring,
with a maximum torsion angle of 2" at the coupling to the
central ring, is almost planar. The C I - P I X 1 3 angle
(101.73(6)") in 3a is about 2" larger than that found in 5 ,
and thus approaches that in uncoordinated phosphinines
(ca. 103"). The C-C bond lengths in the heterocycle are
significantly different; they also alternate in the neighbouring ring.
Bearing in mind the numerous possible structural variants of carbonyl(carbene) complexes, carbene annelation
with phosphaalkynes can be expected to afford direct access to a broad spectrum of functionalized mononuclear
and condensed phosphaarenes.1'61
Experimental
3a, b : A solution of 7.5 mmol of the carbene complex (2.72 g, l a ; 2.82 g I b )
and 0.75 g (7.50 mmol) of 2 in 20 mL of tert-butyl methyl ether was heated
under an argon pressure of 5 bar for 2 h at 50°C. After removal of the solvent
the residue was chromatographed at -25°C with CHZC12/pentane (1/3 to
111) on silica gel. Recrystallization from CHzC12/pentane (111) afforded
dark red crystals. Yields: 2.59 g 3a (82%), 2.41 g 3b (82%).-3a: IR (hexane):
3(C=O)= 1965 (s), 1885 (s, br) c m - ' ; 'H-NMR (400 MHz, CD,COCD,):
6=9.35 (dd, 1 H; 5-H), 8.55 (s, I H; OH), 8.32 (d, 1 H; 10-H), 7.89 (dd, 1 H;
8-H), 7.85 (d, 1 H; 9-H), 7.65 (m, 2 H; 6,7-H), 4.00 (d, 3 H: OCH,), 1.57 (d,
9 H ; C(CH,),): "C-NMR (100.4 MHz, CD,COCD,): 6=233.49 (Cr(CO),),
154.72 (C-2, 'J(P,C)=68.0 Hz), 133.04, 133.65, 131.12, 131.04, 130.07, 129.39,
129.19, 128.71, 123.27, 96.97 (C-4a-C-lOa), 114.73 (C-4, 'J(P,C)=60.1 Hz),
101.06 ( G I , 2J(P,C)=7.7 Hz), 58.93 (OCH3, 'J(P,C)=34.3 Hz), 38.01
(C(CH,),, 'J(P,C)= 19.6 Hz), 31.62 (C(CH,),, 'J(P,C)= 14.2 Hz); "P-NMR
(121.4 MHz, CD,COCD,): 6= -26.50; MS: m / z 434 (MQ).-3b: IR (hexane): 3(C=O)= 1957 (s), 1887 (s, br) c m - ' ; 'H-NMR (CD,COCD,): 6=9.50
(d, 1 H: 5-H), 7.91, 7.89 (each d, each 2 H ; 8,9,10-H, OH), 7.66 (m, 2 H ; 6.7H), 4.30 (dq, 1 H ; OCH), 4.09 (dq, 1 H; OCH), 1.58 (t, 3 H; CH,CH20), 1.57
(d, 9 H ; C(CH,)3); "C-NMR (CD3COCD3): 6=233.67 (Cr(CO),), 153.72 (C2, 'J(P,C)=68.2 Hz), 115.12 (C-4, 'J(P,C)=60.4 Hz), 133.90, 133.70, 131.11,
131.09, 130.17, 129.41, 129.17, 128.60, 123.34, 100.89, 97.04 (C-1, C-4a-CIOa), 70.15 (OCH2, 'J(P,C)=35.3 Hz), 38.03 (C(CH,),, 'J(P,C)= 19.4 Hz),
31.46 (C(CH,),, 'J(P,C)= 14.3 Hz), 15.20 (CHICHIO, 4J(P,C)=4.0 Hz); "PNMR (CD,COCD,): 6 = -24.77; MS: m / z 448 ( M e ) .
4 : A solution of 3b (2 mmol) in ether (40 mL) was heated under a pressure of
30 bar C O for 14 h at 7 0 T . The solvent was then removed and the almost
quantitatively recovered hexacarbonylchromium sublimed under Hg vacuum
at 20°C. Column chromatographic purification of the residue on silica gel
( I O T , ether/pentane as eluent) and recrystallization (pentane/CH2Cll) afforded yellow crystals. Yield: 95%.--'H-NMR (CD,COCD,): 6=9.80 (d,
1 H; 5-H), 8.39 (d, 1 H ; 10-H), 7.88 (m, 3 H ; 8,9-H, OH), 7.61 (m, 2 H ; 6,7-H),
4.48 (4. 2 H ; OCH2), 1.71 (t. 3 H : CHlCH20), 1.68 (d (4J(P,H)), 9 H ;
C(CH,),); "C-NMR (CD3COCD3): 6= 188.74 (C-2, 'J(P,C)=46.6 Hz),
153.97 (C-4, 'J(P,C)=47.5 Hz), 149.71, 133.70, 130.57, 129.43, 129.23, 129.16,
128.43, 127.46, 127.29, 122.99, 122.92 (C-I, C-4a-C-lOa), 68.61 (OCHz,
'J(P,C)=39.3 Hz), 38.94 (C(CH,),, 'J(P,C)=23.7 Hz), 31.64 ( C ( C H h ,
'J(P,C)- 15.4 Hz), 15.39 (CH,CH20), 4J(P,C)=4.1 Hz): "P-NMR
(CD3COCD,): 6 = 125.80: MS: m / z 312 ( M e ) .
Received: December 23, 1987 [Z 2557 IEl
German version: Angew. Chem. 100 (1988) 725
[I] K. H Dotz, R. Noack, G. Miiller, J. Chem. SOC.Chem. Commun. 1988,
302.
7 14
0 VCH Verlagsgesellschaft mbH, 0-6940 Weinheim. 1988
[2] a) G. Becker, G. Gresser, W. Uhl, 2. Naruforsch. 8 3 6 (1981) 16: b) optimized procedure: W. Rosch, U. Hees, M. Regitz, Chem. Ber. 120 (1987)
1645.
131 a) W. Rosch, M. Regitz, Angew. Chem. 96 (1984) 898; Angew. Chem. Int.
Ed. Engl. 23 (1984) 900; b) W. Rosch, H. Richter, M. Regitz, Chem. Ber.
120 (1987) 1809 and previous reports of this series.
I41 a) P. Binger, R. Milczarek, R. Mynott, M. Regitz, W. Rosch, Angew.
Chem. 98 (1986) 645; Angew Chem. Inr. Ed. Engl. 2s (1986) 644; h) P. B.
Hitchcock, M. J. Mah, J F. Nixon, J. Chem. Sac. Chem Commun. 1986.
737; c) P. Binger, R. Milczarek, R. Mynott, M. Regitz, J. Organomer.
Chem. 323 (1987) C35; d) R. Milczarek, W. Riisseler, P. Binger, K. Jonas, K. Angermund, C. Kriiger, M. Regitz, Angew. Chem. 99 (1987) 957:
Angew. Chem. Inr. Ed. Engl. 26 (1987) 908; e) A. R. Barron, A. H. Cowley, ibid. 99 (1987) 956 resp. 26 (1987) 907; 0 M. Driess, D. Hu, H. Pritzkow, H. Schaufele, U. Zenneck, M. Regitz, W. Rosch, J. Organomer.
Chem. 334 (1987) C35.
I51 Reviews: a) K. H. Dotz, Angew. Chem. 96 (1984) 573; Angew. Chem. Int.
Ed. Engl. 23 (1984) 587; b) K. S. Chan, G. A. Peterson, T. A. Brandvold,
K. L. Faron, C. A. Challener, C. Hyldahl, W. D. Wulff, J. Orgonomer.
Chem. 334 (1987) 9: c) K. H. Dotz, M. Popall, G. Miiller, h i d . 334 (1987)
57: d) K. H. Dotz in H. tom Dieck, A. de Meijere (Eds.): Organomeralhcs in Organic Synthesis: Aspects of a Modern Interdisciplinary Field,
Springer, Berlin 1988.
[6] Recent examples: a) K. H. Dotz, M. Popall, Terrahedron 41 (1985) 5797;
b) M. F. Semmelhack, J. J. Bozell, L. Keller, T. Sato, E. J. Spiess, W. D.
Wulff, A. Zask, h i d . 41 (1985) 5803; c) W. D. Wulff, P.-C. Tang, K. S .
Chan, J. S. McCallum, D. Y . Yang, S . R. Gilbertson, ibid. 41 (1985)
5813; d) A. Yamashita, J . Am. Chem. Soc. 107 (1985) 5823; e) K. H.
Dotz, M. Popall, Angew. Chem. 99 (1987) 1220: Angew. Chem. i n t . Ed.
Engl. 26 (1987) 1158.
[7] 5 : "P-NMR: 6 = -4.3; J. Deberitz, H. Noth, Chem. Ber. 103 (1970)
2541.
I81 a) K. H. Dotz, J. Miihlemeier, U. Schubert, 0. Orama, J. Organornet.
Chem. 247 (1983) 187: b) a predominantly electronic stereocontrol is assumed in the regiospecific 13 +2]-cycloaddition of 1.3-dipoles to 2, see,
e-g., [2b].
[9] Cf. K. H. Dotz, J . Organomer. Chem. 140 (1977) 177.
[lo] K. W. Muir, G. Ferguson, G. A. Sim, J . Chenz. Soc. B1968. 467.
[ I I] Crystal structure data of 3 a : space group P2,/c, a = 10.334(3),
b = 11.834(1), c = 16.445(2) A, fl= 102.33", Z = 4 . CAD-4 (Enraf-Nonius)
four-circle diffractometer, MoKnradiation, graphite monochromator, wscans, 8= 2-25", 3766 measured reflections. Solution by direct methods,
refinement to R= 0.030 for 2679 independent reflections with i> 3~(1),
all non-hydrogen atoms anisotropic, H-atoms riding with fixed isotropic
temperature factors. Further details of the crystal structure investigation
are available on request from the Fachinformationszentrum Energie,
Physik, Mathematik GmbH, D-7514 Eggenstein-Leopoldshafen 2
(FRG), on quoting the depository number CSD-52863, the names of the
authors, and the journal citation.
[I21 H. Vahrenkamp, H. Noth, Chem. Ber. I05 (1972) 1148.
1131 K. H. Dotz, R. Dietz, A. von lmhof, H. Lorenz, G. Huttner, Chem. Ber.
109 (1976) 2033.
[I41 a ) G. Huttner, B. Krieg, Angew. Chem. 83 (1971) 541; Angew. Chem. Int.
Ed. Engl. I0 (1971) 512; b) G. Huttner, 0. S . Mills, Chem. Ber. 10s
(1972) 301.
[I51 a) W. Fischer, E. Hellner, A Chatzidakis, K. Dimroth, Tetrahedron Lett.
1968. 6227; b) J. C. J. Ban, J. J. Daly, Angew. Chem. 80 (1968) 843:
Angew. Chem. h i . Ed. Engl. 7(1968) 811.
1161 So far only very few condensed phosphaarenes have been described. Review: G. Mark1 in Houben- Weyl-Muller, Merhoden der Organischen
Cliemie l4rh edit.). Vol. E 1. Thieme, Stuttgart 1982, p. 72 ff.
Inductivity and Bridging in
Ammonium and Carbenium Ions
By Cyril A . Grob," AIfred Dratva, Martin Griindel, and
Guangyi Wang
The reactivities of the cationic centers in ammonium and
carbenium ions are fundamentally different. Thus, in the
first case the N atom is tetracoordinate and, hence, inert to
nucleophiles. In the second case the C-atom is tricoordinate and so electrophilic that it reacts even with weak nucleophiles.
[*I Prof. Dr. C. A. Grob, Dr. A. Dratva, Dr. M. Griindel, Dr. G. Wang
Institut fur Organische Chemie der Universitat
St.-Johanns-Ring 19, CH-4056 Basel (Switzerland)
0570-0833/88/050S-O714 $ 02.50/0
Angew. Chem. lnt. Ed. Engl. 27 (1988) No. 5
The differences are also reflected in the way the inductive (0 effect of substituents control the formation of these
cations. This is demonstrated by application of the Hummeft equation Ig(K/Ko)=pl.aq to the protonation of the
bi- and tricyclic amines 1-4, and to the solvolysis rates of
the corresponding p-toluenesulfonates 5 - 8 . K and K O are
1
b
3
2
OTos
5
6
7
8
equilibrium o r rate constants for the substituted“’ and unsubstituted compounds, respectively; 07 are inductive substituent constants.[21The reaction constants p , are of primary importance because they serve as a measure of the
i n d ~ c t i v i t y , ‘i.e.
~ ] of the intensity with which the I effect of
the substituents is transmitted to the reaction center.
The pK,, values of the hydroperchlorates of the amines
1-4141 as well as the logarithms of the rate constants for the
solvolysis of the toluenesulfonates 5 - 8 in 80% ethanol[51
correlate linearly with the corresponding op values. Therefore, the protonation of the amines, as well as the ionization of the toluenesulfonates, are determined primarily by
the I effect of the substituents. The p , values, as calculated
from the slopes of the plots of IgK vs. a?,are listed in
Table 1. In the case of the amines 1-4 they are 1.03
(kO.02); i.e. t h e p , values, like the distances between the N
atoms and the substituents, are practically the same. Therefore, inductivity is not dependent on the structure of the
molecules.
Table I . lnductivitiesp, of the amines 1-4 and of the toluenesulfonates 5-8
(correlation coefficients in brackets). R =general substituent [ I ] (see formulas).
Compounds
1.05 (0.994)
1.01 (0.984)
1.04 (0.994)
1.00 (0.999)
- 2.00
- 0.72
~
1.50
- 0.80
In contrast, the pI values for the dissociation of the toluenesulfonates 5 - 8 to the ion pairs 9-12 differ markedly,
although the distances and the partial structures are again
practically the same. In these cases then, inductivity depends on the structure of the whole molecule. The large
variations of p , have been attributed to the varying tendency for dorsal and temporarily pentacoordinate C-atoms
to bridge the electrophilic centers in the cations 9-12,’3.51
Anqew. Chem In1 Ed. Engl. 27 (1988) No. 5
9
11
10
12
for bridging contributes substancially to the transmission
of the I effect. As a directional bonding interaction, bridging generates strain which varies according to the structure
of the molecule. Bridging strain is small in the cations 9
and 11, but considerably larger in 10 and 12.16]
As shown by the p , values for protonation of the 2-, 3-,
and 4-substituted quinuclidines 13”l and for the solvolysis
of the corresponding bicyclo[2.2.2]octyl p-nitrobenzenesulfonates 14,“’ inductivity is considerably higher at C2 than
at the more remote C atoms in both cases. Furthermore, p ,
is distinctly higher at C2 in 13 than in 14. This difference
could be due to the presence of the anion in the contact
ion pair 15 which partially shields the positive charge at
C 1 and thereby diminishes the I effect of neighboring substituents. On the other hand, the pI values at C3 and C4 in
14 are slightly larger than at these positions in 13, an indication that these carbons are weakly bridged.
- 1.00
-1.22
-1.00
-1.5L
ONs
13
11
OONs
15
From these results it can be concluded that the transmission of inductive substituent effects in ammonium and carbenium ions differs in that in the first case it involves only
structure-independent polarization, whereas in carbenium
ions transmission also involves structure-dependent, shortrange bridging. It should be noted, however, that the concept of graded bridging is derived from observed inductivitiesr3’ and differs from the concept of “classical” and
“nonclassical” ions, as employed by Winstein et a1.[9”1and
other a ~ t h o r s . ~ ~ ~ ~ ‘ ~
Received: December 21, 1987 [ Z 2550 IE]
German version: Angew. Chem. 100 (1988) 123
PI
6-exo-R-2-azanorbornanes
1
7-anti-R-2-azanorbornanes 2
6-exo-R-2-azabicyclo[2.2.2]octane
3
4e-R-2-azaadamantanes 4
6-exo-R-2-exo-norbornyltoluenesulfonates
5
7-an~r-R-2-endo-norbornyltoluenesulfonates
6
6-exo- R-2-e.~~-bicyclo[2.2.2]octyltoluenesulfonates
7
4e-R-2e-adamantyltoluenesulfonates 8
wO T o s
I n each case, eight to twelve different substituents R were introduced.
C. A. Grob, B. Schaub, M. G. Schlageter, Helu Chim. Acta 63 (1980)
57.
C. A. Grob, Arc. Chem. Res. 16 (1983) 426.
The preparation of the amines and the pK, measurements are described
in the dissertations by A. Dratva, M. Griindel, and G. Wang (Universitatsbibliothek Basel, 1987).
W. Fischer, C. A. Grob, R. Hanreich, G. von Sprecher, A. Waldner, Helu.
Chim. Acta 64 (1981) 2298; P. Flury, C. A. Grob, ibid. 66 (1983) 1971: C .
A. Grob, P. Sawlewicz, ibid. 67 (1984) 1906; C. A. Grob, G. Wittwer, K.
Rama Rao, ibrd. 68 (1985) 651.
Strong bridging, as in 9 (R=H), leads to substitution with retention,
weak bridging, a s in 12 ( R = H) to substitution with retention and inversion.
C. A. Grob, Helu. Chim. Acra 68 (1985) 882.
R. Bielmann, C. A. Grob, D. Kury, G. W. Yao, Helu. Chim. Acta 68 (1985)
2158.
a) S . Winstein, D. S . Trifan, J . Am. Chem. Soc. 71 (1949) 2953; ;hid. 74
(1952) 1147, 1154; b) P. von R. Schleyer, D. Lenoir, P. Misson, G. Liang,
G. K. Surya Prakash, G. A. Olah, ibrd. 102 (1980) 683; c) G. A. Olah, G.
K . Surya Prakash, M. Sauders, Acc. Chem. Res. 16 (1983) 440.
0 VCH Verlagsgesel1scha& mbH, 0-6940 Weinheim. 1988
0570-0833/88/0505-07IS $ 02.50/0
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