M.T. Lockhart et al. / Journal of Organometallic Chemistry 582 (1999) 229–234
233
straction reaction by aryl radicals from CH3CN com-
petes with the coupling reaction with Ph3Sn− ions.
was added to the solution of the nucleophile before
substrate addition.
4. Experimental
Acknowledgements
4.1. General methods
This work was supported in part by the Consejo de
Investigaciones de la Provincia de Co´rdoba (CONI-
COR), Comisio´n de Investigaciones de la Provincia de
Buenos Aires (CIC) and the Consejo Nacional de In-
Irradiation was conducted in a reactor equipped with
four 250 W UV lamps emitting maximally at 350 nm
(Philips model HPT, water-refrigerated).
vestigaciones Cient´ıficas
Argentina.
y
Te´cnicas (CONICET),
4.2. Materials
Reagents were available commercially and were used
as received, unless otherwise indicated. Ph3SnH was
prepared by the reaction of Ph3SnCl (Fluka) and
LiAlH4 as reported [14]. DMSO and CH3CN were
vacuum distilled from CaH2 and stored with molecular
sieves. The products were quantified by glc with the
internal standard method, compared with an authentic
sample. p-Anisyltriphenyltin [15], p-bis(triphenylstan-
nyl)benzene [16], 2-pyridyltriphenyltin [17] and 3-
pyridyltriphenyltin [17] were synthesized by known
methods.
References
[1] K.R. Wursthorn, H.G. Kuivila, G.F. Smith, J. Am. Chem. Soc.
100 (1978) 2789.
[2] (a) H.G. Kuivila, K.R. Wursthorn, J. Organomet. Chem. 105
(1976) C6. (b) K.R. Wursthorn, H.G. Kuivila, G.F. Smith, J.
Organomet. Chem. 140 (1977) 29.
[3] (a) J.P. Quintard, S. Hauvette-Frey, M.J., J. Organomet. Chem.
112 (1976) C11; (b) J. Organomet. Chem. 159 (1978)147.
[4] C.C. Yammal, J.C. Podesta, R.A. Rossi, J. Org. Chem. 57 (1992)
5720.
[5] C.C. Yammal, J.C. Podesta, R.A. Rossi, J. Organometal. Chem.
509 (1996) 1.
[6] For reviews, see: (a) R.A. Rossi, R.H. de Rossi, Aromatic
Substitution by the SRN1 Mechanism; ACS Monograph 178;
Washington, DC 1983. (b) W.R. Bowman, Chem. Soc. Rev. 17
(1988) 283. (c) R.K. Norris, in: B.M. Trost (Ed.), Comprehensive
Organic Synthesis, vol. 4, Pergamon, New York, 1991, p. 451.
(d) R.A. Rossi, A.B Pierini, A.B. Pen˜e´n˜ory, in: S. Patai, Z.
Rappoport (Eds.), The Chemistry of Functional Group, Wiley,
Chichester, Supl. D2, Ch 24, 1995, p.1395.
[7] Liquid ammonia has been the most widely used solvent in SRN1
reactions. However, based on reactivities of different
nucleophiles, it has been shown that DMSO and CH3CN are
suitable solvents by this type of mechanism, despite they
are better hydrogen donors than liquid ammonia. See (a)
J.F. Bunnett, R.G. Scamehorn, R.P. Traber, J. Org. Chem. 41
(1976) 3677. (b) M.P. Moon, J.F.Wolfe, J. Org. Chem. 44 (1979)
4081.
[8] J.K. Stille, Angew. Chem. Int. Ed. Engl. 25 (1986) 508. For a
review see: V. Farina, V. Krishnamurthy, W.J. Scott, in: L.A.
Paquette, Ed.), The Stille Reaction, Organic Reactions, vol. 50,
1997.
[9] The pKa of Ph3SnH is ca. 16 (E.S. Petrov, M.I. Terekhova, R.G.
Mirskov, M.G. Voronkov, A.I. Shatenshtein, Dokl. Akad.
Nauk. SSSR, 221 (1975) 111; Chem. Abstr. 82 (1975) 155040e),
lower than that of t-BuOH in DMSO (32.2) (F.G. Bordwell,
Acc. Chem. Res. 21 (1988) 456).
4.3. Photostimulated reaction of 1 with Ph3SnK in
DMSO
The following procedure is representative of all the
reactions. The reactions were carried out in a two-
necked 50 ml, round-bottomed flask equipped with a
nitrogen inlet, and a magnetic stirrer, and the outlets
were sealed with septa. Then, 0.78 mmol of Ph3SnH in
10 ml of degassed DMSO was added by syringe fol-
lowed by t-BuOK (0.8 mmol). Then a solution of 0.082
ml (0.6 mmol) of 1 in 1 ml of DMSO was added. The
solution was irradiated 4 h under continuous stirring.
The reaction was quenched by the addition of methyl
iodide in excess and 10 ml of water, and then extracted
with diethyl ether. The products were quantified by
GLC with the internal standard method (72% yield),
compared with an authentic sample synthesized by a
known procedure [18].
4.4. Reaction of 1 with Ph3SnK in DMSO in the dark
[10] Besides the reduction product, Ph3SnI was obtained, together
with Ph3SnOH and (Ph3Sn)O, indicating that this is an HME
reaction.
[11] (a) F. M’Halla, J. Pinson, J.M. Save´ant, J. Am. Chem. Soc. 102
(1980) 4120. (b) C. Amatore, J. Pinson, J.M. Save´ant, A.
Thie´bault, J. Am. Chem. Soc. 104 (1982) 817.
The procedure was similar to that for the previous
reaction. In this case, however, the reaction flask was
wrapped with aluminium foil.
4.5. Photostimulated reaction of 1 with Ph3SnK in
DMSO in the presence of p-DNB
[12] C.T. Gautier, M. Genesty, C. Degrand, J. Org. Chem. 56 (1991)
3452.
[13] It is known that in liquid ammonia ketone enolate ions do not
react spontaneously with haloarenes, but they do so in DMSO as
solvent. See (a) R.G. Scamehorn, J.F. Bunnett, J. Org. Chem. 42
The procedure was similar to that for the previous
reaction, except that in this case 20 mol.% of p-DNB