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J. Org. Chem. 1984,49, 3556-3559
and it appears that tosylates and chlorides are reduced entirely by an s N 2 pathway. In the case of alkyl bromides, it appears that SN2and SET are in competition, with sN2 being strongly favored expept when a very stable radical such as the trityl radicd is produced. However, for alkyl iodides it appears that SET is the major reaction pathway for reduction by LiA1H4 and AlH3. Further detailed studies have shown that LiA1H4 and AlH3 are both responsible for the observed electron transfer phenomena. Studies of reductions of optically active halides are consistent with the results of the cyclizable probe studies in that a high degree of inversion in the product is observed for tosylates, chlorides and bromides. However, the reduction of 2-iodooctane by LiAlD4proceeds with much less
stereospecificity than reduction of the other 2-halooctanes, indicating the presence of radical intermediates in this reaction.
Acknowledgment. We are indebted to the National Science Foundation Grant No. CHE 78-00757 for support of this work. Registry No. 4, 928-89-2; 5, 2695-47-8; 6, 18922-04-8; 7, 89745-98-2; 8, 76695-77-7; 9, 56068-49-6; 10, 77400-57-8; 11, 15661-92-4; 12, 38334-98-4; 13, 13389-36-1; 16, 27770-99-6; 17, 16844-08-9; 18, 1191-24-8; 19, 1809-04-7; 20, 3756-41-0; 21, 3756-40-9; Ph,CHCl, 90-99-3; Ph2CHBr, 776-74-9; LiAIH4, 16853-85-3;LiAlD4,1412854-2; AMs, 7784-21-6;MgH2,7693-27-8; fIMgC1, 22106-77-0; LiEt,BH, 22560-16-3; Li(t-BuO),AlH, 17476-04-9;iron, 7439-89-6.
O n the Sulfur-Nitrogen Bonding Character of N-Arylsulfilimines Shinji Tsuchiya,*J Shun-ichi Mitomo,l Manabu Sen6,l and Hiroshi Miyamae2 Institute of Industrial Science, University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo 106, Japan, and Department of Chemistry, Faculty of Science, Josai University, Keyakidai,' Sakado-Shi, Saitama 350-02, Japan Received February 2, 1984
The S-N bonding character of N-arylsulfiiiminewas investigated by X-ray structure determination and X-ray photoelectron spectroscopy (XPS). The crystals of sulfiimine I are monoclinic, space group A2/a, in a unit cell of dimension a = 16.726 A, b = 25.877 A, c = 5.676 A, y = 118.29O. The positions of hydrogen atoms were also determined. The data of structure determinations and XPS suggest that the d r p n interaction between the sulfur and the nitrogen is not important, but the N-arylsulfilimineaare stabby other factors with the resonance interaction of the p-nitrophenyl moiety, i.e., the strong interaction through the bond between the sulfur and the nitrogen and the hyperconjugative effect. The multipeak structure due to shake up transition was observed in N 1s peaks of the nitro group of N-arylsulfilimines and it was found that there is a correlation between the energy separation of doublets and the resonance interaction of the aryl ring. (r
Introduction The bonding character in sulfiiimines has been studied by a number of investigat" However, the problem of the exact bonding character in sulfilimine remains uncertain, because it is extremely difficult to determine the degree of contribution of many factors such as electronwithdrawing effect of substituents, dn-pr interaction, etc.4 The ability of the sulfur atom to stabilize an adjacent negative charge remains a interesting phenomenon. For example, Epiotis et al. reported the hyperconjugative stabilization associated with the interaction of the carbon lone pair orbital with the antibonding u orbital of an adjacent sulfur; the enhanced stability of a carbanion adjacent to sulfur is dominated by the nC-u*SH stabilizing interaction and not by dn-pr conjugation.6p6 In addition, the contribution of the hyperconjugative effect related to n p ~ * interaction s for the stability of sulfonium ylides was (1) Institute of Industrial Science, University of Tokyo. (2) Department of Chemistry, Faculty of Science, Josai University. (3) Gilchrist, T. L.; Moody, C. J. Chem. Rev. 1977, 77,410. Trost, B. M.; Melvin, L. S., Jr. 'Sulfur Ylides"; Academic Press: New York, 1975. Johnson, A. W. "Ylid Chemistry"; Academic Press: New York, 1966. (4) Bernardi, F.; Schlegel, H. B.; Whangbo, M. H.; Wolf, S. J. Am. Chem. SOC. 1977,99,5633. Dixon, D. A.; Dunning, T. H., Jr.; Eades, R. A.; Gassman, P. G. Zbid. 1983,105,7011. Glass, FL 5.; Bucheck, J, R. Ibid. 1976,98,965. Boyd, D. B.; Hoffmann, R. Zbid. 1971,93,1063. Mixan, C. E.; Lambert, J. B. J. Org. Chem. 1973,38,1350. Kucsman, A.; Ruff, F.: Kooovita. I. Tetrahedron 1966. 22. 1575.
'(5) Epiotis, N. D.; Yaks, R. L.; Bernardi, F.; Walfe, S. J. Am. Chem. SOC. 1976,98,5435. (6) Lehn, J. M.; Wipff, G. J. Am. Chem. SOC. 1976,98, 7498.
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discussed by the Fava group' and the Heathcock group? On the other hand, Streitwieser et al. concluded by ab initio SCF-MO calculations that the sulfur of thiomethyl anion stabilizes carbanions by polarization rather than by d orbital conjugation? We have also reported a stabilizing effect, which we termed the electron displacement effect, in the N+-N- bonding of aminimides which do not have d orbital available.f0 This effect means that the electron cloud of the u bond between N+ and N- in aminimide lies closer to the quaternary nitrogen (N+) and consequently, the electron density of the anionic nitrogen (N-) decreases and the aminimide is stabilized. We also found evidence that the anionic nitrogen of the carbonyl stabilized sulfilimine is stabilized by the electron displacement effect." On the other hand, as the ability of N-aryl substituent to stabilize the anionic nitrogen is very different from that of the carbonyl group or the sulfonyl group, the bonding character of stable N-arylsulfiilimines has been studied by several physical measurements and chemical reactivities.12 (7) Andreetti, G. D.; Bernardi, F.; Bottoni, A.; Fava, A. J. Am. Chem. Soc. 1982, 104, 2176. (8) Graham, S. L.; Heathcock, C. H. J. Am. Chem. SOC. 1980, 102, 3713. 1975, (9) Streitwieser, A., Jr.; Williams, J. E., Jr. J. Am. Chem. SOC. 97, 192. (10) Tsuchiya, S.; Sen6, M. J. Org. Chem. 1979,44,2850. Tsuchiya, S.; Sena, M. J. Chem. Soc., Dalton Trans. 1984,731. Tsuchiya, S.; Sen6, Perkin Trans. 2 1983,887. Tsuchiya, S.; M.; Lwowski, W. J.Chem. SOC. Sen6, M.; Lwowski, w. J. Chem. Soc., Chem. Commun. 1982,875. (11) Tsuchiya, S.; Sen6, M. J. Chem. Soc., Chem. Commun. 1983,413.
0 1984 American Chemical Society
S-N Bonding Character of N-Arylsulfilimines
Figure 3. Bond length (A) and bond angles in N-arylsulfilimine I.
For example, Eliel e t al. reported that the percent ionic character of the S-N bonding of N-(p-nitropheny1)-S,Sdimethylsulfilimine (11) would seem to range from 49% to 60% and the dipole form predominates only when there are strongly electron-withdrawing substituents at the para position in the benzene ring. However, there remains the question regarding the factors of covalent c~ntribution.'~ In this study, we investigated the bonding character of the S-N bond of N-arylsulfilimines by means of X-ray structure determinations and X-ray photoelectron spectroscopy (XPS). It is clarified that N-arylsulfilimines are stabilized by other factors with the resonance interaction of the aryl ring due to the electron-withdrawing effect of the nitro group.
Results and Discussion The molecular geometry and the molecular packing of N-arylsulfilimine I, determined by X-ray diffraction, are
sulfilimine I
available as supplementary material (Figures 1and 2). The structure with bond lengths and bond angles in sulfiiliiine I is shown in Figure 3. Tables I-111, listing final fractional coordinates and anisotropic thermal parameters, all bond lengths, valence angles, and torsion angles, are also available as supplementary material. The positions of hydrogen atoms were also determined. The crystal structure of N-(p-nitropheny1)-S,S-dimethylsulfilimine (11) was already reported by Eliel and his co-~orkers.'~It is very interesting to compare the results of the structure analysis of sulfilimine I with that of sulfilimine 11. The structure of sulfilimine I is similar to that of sulfilimine I1 reported. That is, as the torsion angle S-N(l)-C(l)-C(2) is -3.4', the moiety of SN-C6H,N02 is almost planar. This planarity is also supported by the data of the derivation of atoms from planes for various portions of the molecular framework as shown in Table IV, which is available as supplementary material. The S-N(1) bond length and the C(1)-N(1)-S angle are 1.649 A and 114.7', respectively (for sulfilimine 11, 1.651 A and 116.1'). The S-N bond length (1.649 A) is intermediate between that in N-acylsulfilimine and Ns~lfonylsulfilimine.'~As the sulfur atom of sulfilimine I (12) Claus, P. K.; Vierhapper, F. W.; Willer, R. L. J.Org. Chem. 1979, 44,2863. Bailer, J.; Claus, P. K.; Vierhapper, F. W. Tetrahedron 1980, 36,901. Varkey, T. E.; Whitfield, G. F.; Swern, D. J. Org. Chem. 1974, 39,3365. Franz, J. A.; Martin, J. C. J. Am. Chem. SOC.1973,95,2017. (13) Eliel, E. I,.;Koskimies, J.; Mcphail, A. T.;Swem, D. J.Org. Chem. 1976,41, 2137.
J. Org. Chem., Vol. 49, No. 19, 1984 3557 is as part of tetrahydrothiophene moiety, the mean valency angle (100.5') a t the pyramidal sulfur atom is slightly smaller than the corresponding angles of sulfiimine I1 and analogous compounds. However, the striking difference is found in the bond lengths and the bond angles of N-C6H4N02moiety. That is, the bond lengths of sulfiilimine I (N(1)-C(l) 1.378 A, C(2)-C(3) 1.382 A, and C(4)-N(2) 1.453 A) are longer than those of sulfilimine I1 (N(l)-C(l) 1.341 A, C(2)-C(3) 1.358 A, and C(4)-N(2) 1.419 A). The bond lengths (C(l)-C(2) 1.423 A, C(2)-C(3) 1.382 A, and C(3)-C(4) 1.395 A) and the endocyclic bond angles (at C(1) 117.9', a t C(4) 122.2', a t C(2,6) 121.2', and a t C(3,5) 118.8') of the benzene ring in sulfilimine I are very different from those in sulfilimine 11. This p-nitrophenyl moiety stabilizes the anionic nitrogen and reduces the character of double bonding between the sulfur and the nitrogen owing to the resonance interaction as shown in A. Thus, the longer bond lengths in sulfilimine I suggest
=s;, -
'0-
A
a smaller contribution of the resonance interaction of the aryl ring compared with the case of sulfilimine 11. This difference should result from the substituents on the sulfur atom, because the substituents on the sulfur atom are only the different parts between two sulfilimines. The information on interaction between the substituents on the sulfur atom and the p-nitrophenyl group gains from the bond lengths and the bond angles of tetrahydrothiophene and p-nitrophenyl moieties. The difference (10.3') between the exocyclic (C-C(1)-N(1)) angles (126.2' and 115.9') for sulfilimine I is almost the same as that (10') for sulfiilimine 11. One of the SCH2groups is nearly in the plane of SN-C6H4N02in sulfilimine I (C(7)-S-N(l)-C(l) -159.0°), whereas the other SCH2bond extends at 103.7' to that plane (C(l0)-S-N(1)-C(1) 103.7'). These angles suggest that the steric interaction between the tetrahydrothiophene and p-nitrophenyl moieties is not so strong, though one of the C-H bond lengths (0.887 A) of SCHz is considerably shorter than that of the other C-H bond (the other mean C-H bond length of tetrahydrothiophene 1.033 A). The endocyclic bond angle (-CH2S-CH2- 93.8') in sulfilimine I is very different from the bond angle (CH3-S-CH, 99.6') in sulfilimine 11 and this mean valency angle a t the sulfur atom (100.5') is slightly smaller than that (102.1') in sulfilimine 11. This result suggests the deformation of the ring of the tetrahydrothiophene moiety in sulfilimine I. The resonance interaction of the p-nitrophenyl group is affected by the deformation of the ring and consequently, the contribution of the resonance interaction of the aryl ring of type A would be smaller in sulfilimine I. If the da-pir interaction between the sulfur atom and the nitrogen atom works effectively, the S-N bond length becomes shorter as the contribution of A decreases. However, the S-N bond length (1.649 A) of sulfilimine I is in agreement with that (1.651 A) of sulfilimine 11, though the N(1)-C(l)bond len h (1.378 A) of sulfilimine I is longer than that (1.341 ) of sulfilimine 11. Several investigators have reported the contribution of dir-pir interaction between the sulfur atom and the nitrogen atom. However, our results of X-ray structure determination in this study suggest that the dir-pa interaction of the S-N
f
(14) Cameron, A. F.; Hair, N. J.; Morris, D. G . J. Chem. SOC.,Perkin Trans. 2 1973,1951. Kalman, A.: Sasvari. K.: Kucsman.A. J.Chem. Soc., Chem. Commun. 1971, 1447.
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J. Org. Chem., Vol. 49, No. 19, 1984
Tsuchiya et al.
Table V. N 1s and S 2p Binding Energies of N-Arylsulfiliminies (eV) sulfilimine I C
S
N
o-N
sulfilimine I1
O
405.4-403.1
397.0
164.4
406.0-403.3
397.1
165.0
z
(w3iiSN-+Noi -
bonding is not important. Thus, it is expected that the electron density on the anionic nitrogen (N(1)) of sulfilimine I is higher than that of sulfilimine 11, because the degree of delocalization of the electron on the anionic nitrogen owing to the resonance interaction of the aryl ring decreases. In order to probe the electron density on the sulfur atom and the nitrogen atom, N 1s and S 2p binding energies of sulfilimines were measured by X-ray photoelectron spectroscopy (XPS).'O N 1s and S 2p binding energies were summarized in Table V and the N l e spectrum of sulfilimine I is available as supplementary material. The N 1s binding energy (397.0 eV) of the anionic nitrogen of sulfilimine I is in excellent agreement with that (397.1 eV) of sulfilimine I1 as shown in Table V. As the correlation between the binding energy and the formal charge of the atom was established, this indicates that the electron density on the anionic nitrogen of sulfilimine I is the same as that of sulfilimine 11. Two main factors to account for this result are suggested. One is the hyperconjugative stabilization associated with the interaction of the nitrogen lone pair orbital with the antibonding a orbital of an adjacent S-C bond ( n r a * s interaction) like the explanation of the stabilization of the S-C ylide by the Fava groupa7 Certainly, the mean SCH2 bond length of sulfilimine I is 1.823 A, which is longer than the mean SCH, bond length (1.786 A) of sulfilimine III2 and the mean SCH2bond length (1.814 A) of 8-methyl-8-thioniabicyclo[4.3.0]nonane tetrafluoroborate.' However, it is considered that the bond length between the sulfur atom and the carbon atom would be affected by the ring structure and the difference in overlapping of orbitals. Thus, the hyperconjugative effect related to n r a * s interaction is one of the possibilities explaining these results. Another factor is the electron displacement effect;'O the electron cloud of the a bond between S+ and N- lies closer to the sulfur atom, the electron density of the anionic nitrogen decreases, and the sulfiilimine is stabilized. It was reported that this effect is one of the stabilizing factors in carbonyl stabilized sulfilimines.ll The information on this effect can gain from the S 2p binding energies of sulfilimines. The S 2p binding energy (164.4 eV) of sulfilimine I is lower than that (165.0 eV) of sulfilimine 11. This is the mean value of several measurements and the difference (0.6 eV) between two sulfilimines would be essential, though the contribution of lattice energy, reorganization energy, and coulombic potentials have to be considered. The lower S 2p binding energy suggests a slight increase of electron density on the sulfur atom of sulfilimine I compared with that of sulfilimine 11. The increase of electron density does not arise from the d?r-p?r interaction, because both S-N(l) bond lengths of sulfilimine I and I1 are the same as described above. Thus, it seems that this interaction between the sulfur atom and the nitrogen atom occurs through the a bond, which is the electron displacement effect. That is, the resonance interaction between the anionic nitrogen and the p-nitrophenyl group decreases and the interaction through the a bond between S+ and N- increases. This interaction
reduces the electron density on the anionic nitrogen (N(1)) by which the sulfilimine is stabilized. Thus, it seems that this effect is also one of the stabilizing factors in N-arylsulfilimines. The Streitwieser group reported that the sulfur atom of thiomethyl anion gains electrons with increased polarization by ab initio SCF MO calculation^.^ The multipeak structures are observed in the N 1s peak of the nitro group of sulfilimines as shown in Figure 4, which is available as supplementary material. We already reported the unusual structures in the -N 1s peak of the nitro group of sulfilimines and interpreted it as being due to the shake-up transitions involving intramolecular charge transfer.16Je It was reported that the energy separation of the doublets increases with increasing electron density on the nitrogen atom attaching to the aromatic ring, because the orbital contraction is less owing to the enhancement of the electron flow toward the electron deficient ~ e n t e r . ' ~ *The ' ~ N 1s binding energy of the anionic nitrogen of sulfilimine I is almost the same as that of sulfilimine 11. However, the energy separation (2.3 eV) of the doublets observed in the nitro group of sulfilimine I is smaller than that (2.7 eV) in sulfilimine 11. It is also clarified that the contribution from the resonance interaction of the aryl ring in sulfilimine I is smaller than that in sulfilimine 11. It seems that the intramolecular charge transfer is dependent upon the degree of the contribution of resonance interaction of the aryl ring. Thus, the energy separation of the N 1s doublets of the nitro group in sulfiimines would be affected by the resonance interaction of the aryl ring A.
Experimental Section The N-arylsulfilimineI was prepared by the published method." The crystal for structure determination was grown in the ethyl ether and hexane solution. Crystal Data. N-arylsulfilimineI, CloH12N202S, M,= 224, monoclinic, a = 16.726 A, b = 25.877 A, c = 5.676 A, y = 118.29O, U = 2163.25 A3, space group = A2/a, 2 = 8. Crystallographic Measurements. A crystal specimen of ca. 0.1 X 0.1 X 0.5 mm was used for X-ray measurements on Rigaku AFC-5 with graphite-monochromated Cu Ka radiation. Unit cell dimensions were determined from a least-squares fit on the basis of 28 28 values (55O < 2 8 < 61°) measured on the diffractometer. Intensities were measured up to 28, = 1 2 5 O with w - 2 8 scan mode and scan speed of 4O/min (3983reflections). They showed monoclinic lattice with space group Aa or A2/a. 1286 reflections with 1 9 3 3a(19) were obtained and used for structure determination. Intensities for two standard reflections measured after every 100 measurements varied by about *0.6% during the data collection. Data were corrected for Lorentz and polarization effects but not for crystal damage, absorption [ ~ ( C Ka) U = 2.49 mm-'1, and extinction. Structure Determination. The phase problem was solved by routine application of direct methods by program MULTAN7819from which positional parameters of the molecule except the carbon atoms in a thiophene ring. The following Fourier synthesis gave the position of the remaining carbon atoms. They were refined assuming anisotropic thermal parameters. (15) Tsuchiya, S.; Sena, M. Chem. Phys. Lett. 1978,54,132. Tsuchiya, S.; Sen6, M. Ibid. 1982, 92, 359. (16) Domcke, W.; Cederbaum, L. S.; Schirmer, J.; Niessen, W. von, Phys. Reu. Lett. 1979,42, 1237. k r e n , H.; Roos, B. 0.; Bagus, P. S.; Geliw, U.; Malmquist, P. A,; Svensson, S.; Maripuu, R.; Siegbahn, K. J. Chem. Phys. 1982,77,3894. Freund, H. J.; Bigelow, R. W. Chem. Phys.
1981, 55, 407. (17) Distefano, G.; Guerra, M.; Jones, D.; Modelli, A.; Colonna, F. P. Chem. Phys. 1980,52, 389. (18) Claw, P. K.; Rieder, W.; Hofiauer, P.; Vilsmaier,E. Tetrahedron 1975, 31, 505. (19) Main, P.; Hall, S. E.; Lessinger, L.; Germain, G.; Declercq, J. P.;
Woolfson, M. M. MULTAN. A System of Computer Programs for Automatic Solution of Crystal Structures from X-ray Diffraction Data. Universities of York,England, and Louvain, Belgium, 1978.
J. Org. Chem. 1984,49,3559-3563 Hydrogen atom were located from differential Fourier syntheses and refmed with isotropic temperature factors. Refinements were accomplished by block-diagonal least-square calculations minimizing wlpd - pc11[2 W = [ a Q 2+ (0.02*FJ21-1] by using programs of UniversaI Crystallographic Computing System 111,UINCS Final R and R, dropped to 0.055 and 0.055, respectively, with maximum shiftlerror ratio of The last differential map showed peaks below 0.21 e A+. Atomic scatteringfactors including anomalous scattering used are those listed in International Tables for X-ray Crystallography.21 All the calculations were carried out on a FACOM M-160F computer. X-ray Photoelectron Spectroscopy. XP spectra were determined by using a JASCO ESCA-1photoelectron spectrometer, and magnesium K a radiation was used as a source. The samples were ground in a agate mortar and dried under high vacuum for a few hours. The fme powder samples were dusted onto a double (20) Sakurai, T.; Kobayashi, K. Rikagaku Kenkyusho Hokoku 1979, 55, 69. (21) ‘International Tables for X-ray Crystallography”;Kynoch Press: P Johnson, C. K., 1971. ORTEP 11. Report 1974; Vol 4, p 71. O R ~ n, ORNL-3794 (revised), Oak Ridge National Laboratory, TN.
3559
sided sticky tape which was mounted on the sample holder. After the sample holder was placed in the sample chamber under high vacuum (1 X 10” Torr) for 2 h, the XPS measurements were performed. To check for radiation damage, C 1s spectra were measured before and after measurements of nitrogen 1s binding energies. Changes in the carbon spectra were not observed. The results of gas analyses by a mass filter (Uthe Technology International) attached to the sample chamber also gave no evidence for the evolution of gaseous decomposition products. All the spectra were run in triplicate and all the peak positions are reported with a precision of *0.20 eV. The C 1s line was taken to be at 284 eV and was used for calibration. Registry No. I, 61157-94-6; 11, 27691-52-7. Supplementary Material Available: Tables I-lV listingfinal fractional coordinates and anisotropic thermal parameters, all bond lengths, valence angles, torsion angles, and the derivation of atoms from planes for various portions of the molecular framework for N-arylsulfilimine I; Figures 1, 2, and 4 showing the molecular geometry, the molecular packing, and N 1s spectrum of N-arylsulfilimine I (7 pages). Ordering information is given on any current masthead page.
sym -1,2-Diarylethylenes from a-Lithiated Benzylic Sulfones. Catalysis by Elemental Tellurium Lars Engman Department of Organic Chemistry, Royal Institute of Technology, S-10044 Stockholm, Sweden
Received February 8, 1984 The stability of a-lithiated alkyl, allyl, and benzyl phenyl sulfones was studied. a-Lithiated benzyl phenyl sulfoneswere found to give sym-1,2-diarylethylenesslowly when kept in tetrahydrofuran at ambient temperature for several days. The reaction time was significantly reduced if a catalyticamount (18-24%) of elemental tellurium was present in the reaction. Other chalcogenides were less effective in this respect. The uncatalyzed reaction produced essentially pure trans olefins whereas the tellurium-catalyzed process afforded substantial amounts of cis isomer (usually 15-35%). Tellurium tetrachloride in chloroform at ambient to reflux temperature was found to be highly effective in promoting cis/trans isomerization of 1,2-diarylethylenes. The involvement of a carbene mechanism or an intermolecular reaction of a-lithiated benzyl phenyl sulfones is considered in a mechanistic discussion.
Introduction The use of sulfones in synthetic organic chemistry is based on the easy formation of a-sulfonyl carbanions and the possibility, after formation of new C-C bonds by alkylation, to remove the SOz moiety by reduction or elimination.’ In a series of papers: Ingold has studied the elimination of sulfinate anions from sulfones and he established the 1,2-elimination as well as the 1,l-elimination reaction. Thus, phenyl @-phenethylsulfone (1)yielded styrene on phS02CH2CH2Fh
phcH2so2Fh
1 z treatment with sodium ethoxide a t 200 O C whereas benzyl phenyl sulfone (2), when fused with KOH a t 200 O C , afforded stilbene (via phenylcarbene). (1) For recent review in the field of sulfone chemistry see: Field, L. Synthesis 1972,101; Zbid. 1978,713. Magnus, P. D. Tetrahedron 1977, 33, 2019. Reid, D. H., Sr. Reporter “Organic Compounds of Sulphur, Selenium and Tellurium”; The Chemical Society; London, 1970; Vol 1; Zbid. 1973; Vol2; Zbid. 1975; Vol. 3; Hogg, D. R. Sr. Reporter, VoL 4; Zbid. 1977; Vol. 5; Zbid. 1979, Vol. 6; Zbid 1981. Block,E. ‘Reactions of Organosulfur Compounds”, Academic Press, New York, 1978. (2) Fenton, G. W.; Ingold, C. K. J. Chem. SOC.1928,3127; Zbid. 1929, 2338, Zbid. 1930,706. Ingold, C. K.; Jeaeop, J. A. J. Chem. Soc. 1930,708.
0022-3263/84/ 1949-3559$01.50/0
The harsh reaction conditions necessary to effect elimination have of course prevented any synthetic use of these processes. However, it was recently found that the 1,2elimination occurred under considerably milder reaction conditions if the resulting olefin was highly ~ o n j u g a t e d . ~ The 1,l-elimination had received little attention up to recently when Julia4 found that a-metalated allylic sulfones were converted by a catalytic amount of Ni(I1) acetylacetonate into symmetrical olefins. Alkyl or benzyl sulfones could also be used,but the best results were obtained by using allylic sulfones (eq 1). NiIIl) RrHSOzPh
M M = Li, Mg R vinyl,alkyl.aryl
RCH=CHR
(1)
(3) See for example: Julia, M.; Amould, D. Bull. SOC. Chim. Fr. 1973, 743; Zbid. 1973, 746. Julia, M.; Badet, B. Zbid. 1976, 1363. Fischli, A.; Mayer, H. Helv. Chim. Acta 1975,58, 1492. Kondo, K.; Tunemoto, D. Tetrahedron Lett. 1975,1007. Olson, G. L.; Cheung, H.-C.; Morgan, K. D.; Neukom, C.; Saucy, G. J.Org. Chem. 1976,41,3287. Manchand, P. S.; Rosenberger, M.; Saucy, G.; Wehrli, P. A.; Wong, H.; Chambers, L.; Ferro, M. P.; Jackson, W. Helv. Chim. Acta 1976, 59, 387. Fischli, A.; Mayer, H.; Simon, W.; Stoller, H.-J. Zbid. 1976, 59, 397. (4) Julia, M.; Verpeaux, J.-N. Tetrahedron Lett. 1982, 23, 2457.
0 1984 American Chemical Society
