4765
Communications to the Editor (2) P. Pino, Adv. Polym.Sci., 4, 393 (1965). (3) C. S. Marvel, R. L. Frank, and E. Prill, J. Am. Chem. SOC., 65, 1647 (1943). (4) S.Murahashi, S. Nozakura, and S. Takeuchi, Bull. Chem. SOC.Jpn., 33, 658 (1960). (5) G. I. Fray and R. Robinson, Tetrahedron, 18, 261 (1962). (6) P. Pino, F. Ciardelli, and G. P. Lorenzi, J. Polym. Sci., Part C, 4, 21 (1963). (7) D. Braun and W. Kern, J. Polym.Sci., Part C, 4, 197 (1963). (8) F. Millich and G. K. Baker, Macromolecules, 2, 122 (1969). (9) (a) R. J. M. Nolte, A. J. M. van Beijnen, and W. Drenth, J. Am. Chem. SOC., 96, 5932 (1974); (b) W. Drenth and R . J. M. Nolte, Acc. Chem. Res., 12, 30 (1979). (10) H. Yuki, K. Ohta, Y. Okamoto, and K. Hatada, J. Polym.Sci., Polym.Lett. Ed.. 15, 589 (1977). (11) K. Ohta. K. Hatada. Y. Okamoto, and H. Yuki. J. Polym. Sci. Polym. Lett. Ed., 16, 545 (1978). (12) H. Yuki. K. Hatada, Y. Kikuchi, and T. Niinomi, J. Polym.Sci. Part E. 6,753 (1968); Polym.J., 1, 36 (1970). (13) II was synthesized from (RbN-(1-phenylethy1)aniline( [ L u ] ~-19.4', ~o c lg/dL, methanol) and n-BuLi in toluene: G. Wittig and U. Thiele, Justus Liebigs Ann. Chem., 726, 1 (1969). (14) (-FSparteine was dried over CaH2 and distilled; [ L U ] ~ ~ O18.0' (c 4.4 g/dL. ethanol). This was mixed with c-BuLl in the molar ratio [sparteine]/[n-BuLi] = 1.2 in toluene at room temperature. Y. Okamoto, K. Urakawa, K . Ohta. and H. Yuki, Macromolecules, 11, 719 (1978). (15) To determine the tacticity and the degree of polymerization, poly(TrMA) was hydrolyzed in methanol containing a small amount of hydrochloric acid and then was converted to PMMA by methylation with diazomethane." (16) The gel permeation chromatographic analysis was accomplished on a JASCO FLC-AI0 instrument with a 50 cm column of Shodex GPC-A80 using THF as eluant. Calibration curve of molecular weight was obtained from polystyrene standards. The number averaged molecular weight of the PMMA was estimated from the elution curve.
-
Yoshio Okamoto, Koichi Suzuki Koji Ohta, Koichi Hatada, Heimei Yuki* Department of Chemistry Faculty of Engineering Science Osaka University, Toyonaka. Osaka 560, Japan Received April 16, I979
Onium Ions. 19.' Chloromethylhalonium Ions Sir:
Table I. ' H and I3C Parameters of Chloromethylmethyl- and Bis(chloromethy1) Halonium Ions
1 4 5 6
7.0 6.8 6.3 6.3 6.2 6.0
7 8
78.5 69.0 37.8 80.4 69.4 38.6
(194.0, t) (1 93.6, t)
(186.8, (191.2, (190.8, (185.2,
t) t) t) t)
a In parts per million from external Me4Si capillary in SO2ClF at -90 to -100 OC. t = triplet, q = quartet. Jc-H in Hz.
Ions 1 and 2 are stable up to -85 "C in SbF5-SO2ClF solution, above which temperature they form difluoromethane. A series of additional chloromethylhalonium ions were prepared by treating ion 1 with several monohalo- and dihaloalkanes. The IH and I3C N M R parameters of the chloromethylhalonium ions formed are given in Table 1. Halonium ions 4 and 5 were formed by treating 1 with bromochloromethane and chloroiodomethane, respectively (reaction 1). The
9ozC1P
!
ClCHzX
IClCH2ClCH,Cll Sb2FlOCI1
When sulfur dioxide is added to a solution of 1, it forms chloromethylated sulfur dioxide 2, whose 'H and I3C N M R
0)
CICHZXCHZCl
-130.C
4, X = Br 5,X.I
bis(chloromethy1)iodonium ion 5 could also be prepared from ClCH2I and HF-SbF5 in SO2 solution a t -50 OC, but attempts to prepare the related bromonium ion 4 in a similar way gave a complex mixture of products. Chloromethylmethylhalonium ions 6, 7, and 8 were also prepared by similar methods (reaction 2). It is interesting to
So2C1P
I
+ CH3X
9ozC1F
+
CH3XCH2CI
-130*C
In our search for nonvolatile and, therefore, safer chloromethylating agents, we report here the first preparation and study of previously unknown chloromethylhalonium ions. When dichloromethane is dissolved in a twofold molar excess of antimony pentafluoride in sulfuryl chloride fluoride solution a t - 130 OC, the bis(chloromethy1)chloronium ion (1) is formed. The N M R parameters of 1 are given in Table I.
50.7 (162.3, q) 39.3 ( 1 62.0, q) 12.2 (158.5,q)
4.3 4.1 3.8
C H 3 P : b P 5 + CICHZX
(2)
-13OOC
X = Cl,Br,I
B,X=CI 1,X=Br 8,X.I
note that the difference between JCH in bis(chloromethy1)halonium ions and the coresponding dimethylhalonium ions is uniformly 30 H z . The ~ same trend is also observed in the chloromethylmethyl halonium ions 6,7, and 8 and between 2 and [CH3O=S=O]+. When dimethyl or chloromethylmethyl ether was added to a solution of 1, oxonium ions 9 and 10 were formed (reaction 3). Attempts to prepare ions 9 and 10 by methylating4 chloXCH.
CH,
ICICH2-0 = S = 01 Sb2FIOC1&H,CI
E shifts are 6~ 7.0 (s) and 6c 88.8 (t), Jc-H = 102.1 Hz. That no chloromethylated S02ClF (3) is formed in the solution of 1 in SO2ClF is apparent from the fact that, if 3 were the ob+
9, X
--
CI
10, X = CI
I
CICHZ-O = S = 0
I P
3
served species, then one would expect its I3C chemical shift to be -1 5 ppm deshielded with respect to the 13Cshift of 2, as is the case in the CH3F-SbF5 system in SO2 and S O Z C I F .Since ~ the opposite trend is noted, 1 must be the observed species, in accord with the fact that CH2Cl2 is a better nucleophile than S02CIF. 0002-7863/79/1501-4765$01 .OO/O
=H
6IH
613c
JCH
6.2
94.9
188.4 Hz
CHI
4.6
11.0
158.1
CI12
6.5
92.1
188.0
CH3
4.9
16.0
159.2
CH2
romethylmethyl ether or bis(chloromethy1) ether (eq 4) gave complex mixtures of ions, which did not include either 9 or 10. Ions 11 and 12 were the major products obtained in each rea ~ t i o n Ion . ~ 11 was also a byproduct in reaction 3. 902 or s O z C l P
CH3F:SbF5
+
XCHZOCHZY
- 7 0 - C to -12ooc
X =Cl, Y = H x=Y=cI
0 1979 American Chemical Society
t
CH2 s 0 - CH2Y
(4)
4166
Journal o f t h e American Chemical Society
Attempts to prepare tris(chloromethy1)oxonium ion from 1 and bis(chloromethy1) ether6 gave only 12. Seemingly 1 attacks preferentially the chloromethyl ethers to form 13a,b, which then easily ionizes to 11 or 12 and CH'C12.
Scheme
/
101.16
/
August I , 1979
I
+ XCHaOCHZCICMZCl
--
x = ri
2
I
I ~ S ,
--
13b,X=CI
Scheme
2
3
I1
The demonstration of the formation of chloromethylhalonium ions and their effective chloromethylating ability opens up the question of the possible chloromethylating ability of related precursors, including methylene chloride, which, consequently, could be of a carcinogenic nature. W e are carrying out further studies relating to the in vitro chloromethylating ability of these systems.
5
4
Acknowledgment. Support of our work by the National Institutes of Health is gratefully acknowledged.
L
References and Notes
a
J
0
,+-
7
6
(1) For part 18, see G. A. Olah, D. J. Donovan, H. C. Lin, H. Mayr, P. Andreozzi, and G. Klopman, J. Org. Chem., 43, 2268 (1978). (2) G. A. Olah, D. J. Donovan, and H. C. Lin, J. Am. Chem. SOC.,98, 2661 (1976). (3) G. A. Olah, "Halonium Ions," Wiley-lnterscience, New York, 1975, and references given therein. (4) G. A. Olah, J. R. DeMember. and R. H. Schlosberg, J. Am. Chem. SOC.,91, 2112 (1969). (5) G. A. Olah and J. M. Bollinger, J. Am. Chem. SOC.,89, 2993 (1967). (6) This highly carcinogenic compound should be handled with great care: J. Natl. Cancer Inst., 43, 481 (1969). All operations involving chloromethyl ethers were carried out in an efficient "carcinogenic hood" with appropriate precautions.
Scheme I11
CH3COCH3
+ 5
7/
\
George A. Olah,* Mark R. Bruce Hydrocarbon Research Institute, Department of Chemistry Uniuersity of Southern California, University Park Los Angeles. California 90007 Received February 12, I979
8
mation of substantial amounts of acetone43 upon carbonylation of equimolar mixtures of l-ds and l-do. To determine whether this intermolecular process is on the direct pathway leading from 1 to 3, we have now prepared 7 (Scheme II), a complex analogous to 1, but having its two cyclopentadienyl rings joined by a methylene group. We find this structural modification allows us to control the intraReaction of a Bridged Binuclear Dialkylcobalt molecularity of the carbonylation reaction by modifying reComplex with Carbon Monoxide and Phosphines. action conditions. In addition, 7 undergoes a remarkable reObservation of Competing Inter- and Intramolecular action with phosphines which sharply restricts mechanistic alternatives for these reactions. Metal to Metal Methyl Transfer Dicyclopentadienylmethane (4) was prepared' as a mixture Sir: of isomers and converted into the binculear tetracarbony15 by the route outlined in Scheme 11. As might be expected if deBis(~5-cyclopentadienylcarbonylmethylcobalt) (1) reacts rapidly with carbon monoxide at ambient temperature, leading composition of l involves initial dissociation into mononuclear to a quantitative yield of ~5-cyclopentadienyldicarbonylcobalt fragments, complex 7 is less reactive than 1, and requires temperatures near 70 O C to achieve carbonylation a t a rea(2) and acetone (Scheme I), a process in which a binuclear sonable rate. Under these conditions, the chemistry of 7 is quite transition metal complex mediates the formation of two new comparable with that of 1, and acetone and tetracarbonyl carbon-carbon bonds. In a previous study,' we established that complex 5 are produced in quantitative yield. Unlike 1, how~5-cyclopentadienylcarbonyldimethylcobalt(3) is an intermediate in this transformation. Labeling studies indicated that ever, the carbonylation can be made to follow a predominantly intra- or intermolecular pathway by varying the concentration an intermolecular process was occurring, resulting in the forTable 1. Isotope Labeling Data Obtained in Crossover Experiments on the Reaction of Mixtures 7-do and 7-d6 with CO and PPh3 startinga c o mr~ l e x total concn. M
7-dn. %
7 - d ~?e' .
0.25 0.05 0.25 0.05 0.25
53 55 46 49 69
47 45 54 51 31
entering lieand
T . "C
dn
70 70 25 25 70
40 52 38 49 69
Cob Cob PPh3' PPh3' PPh3'
acetone products,a 70 di dh 28 5 16 1
3
32 43 46 50 28
molecularity % intra-
7e inter-
44 90 67 98 93
56 IO 33 2 I
I n the carbonylation reactions, where acetone was formed as direct product, it was either isotropically analyzed by G C / M S or purified by preparative GC and then subjected to subsequent MS analysis. In the PPh3 reaction, product 8 was first diluted to a concentration 50.05 M and then carbonylated to generate acetone for analysis (the run at 0.05 M 7 precludes the possibility of significant label scrambling during the carbonylation of 8 a t these concentrations). Toluene solvent. Benzene solvent. 0002-7863/79/ 1501-4766$01.00/0
0 1979 American Chemical Society
