3722
J. Org. Chem. 1999, 64, 3722-3725
Notes New and Facile Synthesis of Symmetrical and Unsymmetrical Diaryl Chalcogenides Using Trivalent Organobismuth Derivatives
xylenes, mesitylene, or DMSO yields in a few hours a mixture of phenyl telluride and diphenyl telluride (eq 1).
Thomas Arnauld,*,† Derek H. R. Barton,‡ and Jean-Franc¸ ois Normant§
It was found that despite the long reaction time (24 h) in the case of benzene and toluene, some Ph3Bi still remained in solution. In xylenes and mesitylene, how ever, Ph3Bi was consumed in a reasonable amount of time (4.5 and 4 h, respectively) with a higher ratio in favor of diphenyl telluride (Ph2Te/Ph2Te2 ) 63/37) with the latter solvent. The ratio was somewhat reversed when heated under reflux of DMSO for 1 h (Ph2Te/Ph2Te2 ) 32/68). Arylbismuthine derivatives are best known for the arylation of amines, enols, and phenols, which they are able to perform with high effectiveness.5 However, only in a very few cases,6 had it been possible to transfer to the functional organic group more than one aryl group out of the three that are available on the bismuth reagent. These arylation reactions could then be considered wasteful because two aryl groups were not utilized. However, in the present case, it must be noted that all the phenyl groups from the bismuth could be accounted for in the two products, Ph2Te2 and Ph2Te. Since phosphines react with elemental chalcogen in boiling toluene or at higher temperatures to yield stable species such as R3PdX,7 it is reasonable to assume that the formation of the analogous bismuth(V) intermediate can constitute the first step in the reaction between Ph3Bi and Te0 (Scheme 1). Ph3BidTe is likely to undergo rapid self-reduction to Ph2BiTePh. The oxidation/selfreduction process could repeat itself once or twice before a ligand coupling finally occurs, yielding the mono- or ditelluride derivative, respectively. In both cases, PhBidTe is generated, which could undergo a redistribution reaction (eq 2), common in bismuth chemistry.8,9 Ph3Bi will therefore be regener-
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, and Laboratoire de Chimie des Organoe´ le´ ments, URA 473 du CNRS, Universite´ Pierre et Marie Curie, Tour 44-45, 4, Place Jussieu, Boıˆte 183, 75252 Paris Ce´ dex 05, France Received October 19, 1998
Introduction A number of syntheses of diaryl chalcogenide derivatives are already available,1 but finding an easy and general method still remains a task of interest. Indeed, among the methods using lithium derivatives, Grignard reagents, and aryl diazonium and aryl iodonium salts, the early syntheses based on Ar2Hg as the aryl donor are still considered as the most general way to obtain symmetrical chalcogenides when reacting on elemental chalcogen2 or unsymmetrical chalcogenides when reacting on a diaryl dichalcogenide.3 However, these methods are often undesirable because of the high toxicity of the diarylmercury salts. Whereas numerous examples of bismuth-chalcogen interactions can be found either in mineralogy or in inorganic chemistry, very few accounts have been reported in the field of organic chemistry.4 Wishing to examine the reactivity of triarylbismuthine derivatives toward chalcogens, we discovered two new reactions allowing the synthesis of symmetrical and unsymmetrical diaryl chalcogenides in good to high yield. Arylbismuthine derivatives are effective aryl donors on amines, enols, and phenols.5 Now they prove to be efficient aryl donors in the preparation of diaryl chalcogenide derivatives. Results and Discussion Heating triphenylbismuthine in the presence of tellurium metal (10 equiv) under reflux of benzene, toluene, † Texas A&M University until March 1999. Universite ´ Pierre et Marie Curie from this date. ‡ In memory of Derek H. R. Barton (deceased March 16, 1998). § Universite ´ Pierre et Marie Curie. (1) The Chemistry of Organic Selenium and Tellurium Compounds; Patai, S., Rappoport, Z., Eds.; John Wiley & Sons: New York, 1986, Vol. 1; 1987, Vol. 2. Magnus, P. D. Comprehensive Organic chemistry; Jones, D. N., Ed.; Pergamon Press: Oxford, 1979; Vol. 3, pp 491-538. Paulmier, C. Selenium Reagents and Intermediates in Organic Synthesis; Baldwin, J. E., Ed.; Pergamon Press: Oxford, 1986. Petragnani, N.; Comasseto, J. V. Synthesis 1986, 1-30. Petragnani, N. Tellurium in Organic Synthesis; Academic Press: London, 1994. (2) Krafft, F.; Lyons, R. E. Chem. Ber. 1894, 27, 1768-1773. (3) Okamoto, Y.; Yano, T. J. Organomet. Chem. 1971, 29, 99-103. (4) (a) Barton, D. H. R.; Dadoun, H.; Gourdon, A. Nouv. J. Chim. 1982, 6, 53-57. (b) Calderazzo, F.; Morvillo, A.; Pelizzi, G.; Poli, R.; Ungari, F. Inorg. Chem. 1988, 27, 3730-3733. (c) Goel, R. G.; Prasad, H. S. Spectrochim. Acta 1979, 35A, 339-344.
heating
Ph3Bi + Te0 98 Ph2Te + Ph2Te2
3PhBidTe f Ph3Bi + Bi2Te3
(1)
(2)
ated,which accounts for the remarkable efficiency of the reaction. We suspect Bi2Te3 to be the side product of the reaction. However, since the insoluble product that is formed during the reaction could not be separated from the excess of Te0 used in the reaction, we have no evidence to support this hypothesis. The procedure was successfully adapted to other triarylbismuthine derivatives (Table 1). The purification required no column chromatography. Instead, the products could be purified using a reduction-extraction (5) (a) Barton, D. H. R.; Finet, J. P. Pure Appl. Chem. 1987, 59, 937946. (b) Finet, J. P. Chem. Rev. 1989, 89, 1487-1501. (c) Suzuki, H.; Ikegami, T.; Matano, Y. Synthesis 1997, 249-267. (6) Arnauld, T.; Barton, D. H. R.; Doris, E. Tetrahedron 1997, 53, 4137-4144. (7) (a) Screttas, C.; Isbell, A. F. J. Org. Chem. 1962, 27, 2573-2577. (b) Zingaro, R. A.; Steeves, B. H.; Irgolic, K. J. Organomet. Chem. 1965, 4, 320-323. (c) Du Mont, W. W.; Kroth, H. J. J. Organomet. Chem. 1976, C35-C37.
10.1021/jo982093x CCC: $18.00 © 1999 American Chemical Society Published on Web 05/14/1999
Notes
J. Org. Chem., Vol. 64, No. 10, 1999 3723 Scheme 1
Table 1. Ar3Bi + Te0 (10 Equiv)a aryl group
time (h)
Ar2Te2b (%)
Ar2Teb (%)
phenyl mesitylc anisyl 1-naphthyl TFMPd
12 24 3 5 30
34
