and copper promoted reactions of cinnamyl sulfide 2i were run in
aromatic solvent at room temperature (Scheme 2).9 Each reaction
gave a similar ratio of diastereomers, as determined by 1H NMR,
which suggests that the silver is not associated with the nucleophilic
carbon on formation of the ylide.
In conclusion, we have shown that a simple silver salt effectively
catalyses the Doyle–Kirmse reaction between diazo compounds
and both allyl and propargyl sulfides. The reaction involves a
straightforward procedure and tolerates a range of substituents
and functionality, including vinyl and aryl bromides, allyl, propar-
gyl, benzyl and PMB units to afford the desired products in high
yields.
Acknowledgements
We thank the EPSRC (EP/E032168/1) and the University of
Birmingham for their financial support of this programme.
Scheme 2 Study of metal source impact on the diastereomeric outcome.
Notes and references
1 (a) W. Kirmse and M. Kapps, Chem. Ber., 1968, 101, 994; (b) M. P.
Doyle, J. H. Griffin, M. S. Chinn and D. van Leusen, J. Org. Chem.,
1984, 49, 1917; (c) M. P. Doyle, M. A. McKervey and T. Ye, Modern
Catalytic Methods for Organic Synthesis with Diazo Compounds, Wiley-
Interscience, New York, 1998; (d) A.-H. Li, L.-X. Dai and V. K.
Aggarwal, Chem. Rev., 1997, 97, 2341. For examples see: (e) D. S.
Carter and D. L. Van Vranken, Org. Lett., 2000, 2, 1303; (f) Y. Kato,
K. Miki, F. Nishino, K. Ohe and S. Uemura, Org. Lett., 2003, 5,
2619.
When prenylsulfide 2j was treated under our standard condi-
tions, sulfide 6j was isolated. Loss of the prenyl unit presumably
occurs after formation of the sulfur ylide. The use of prenylsulfide
2k bearing a more electron-donating substituent led to a moderate
yield of the desired product 4k incorporating the prenyl unit,
alongside smaller amounts of 6k. Activated molecular sieves
were added to the reaction to further minimise the amount of
adventitious water present. A slight increase in the yield of 4k was
achieved under these conditions.
2 P. W. Davies and S. J. C. Albrecht, Chem. Commun., 2008,
238.
3 (a) R. Prabharasuth and D. L. Van Vranken, J. Org. Chem., 2001, 66,
5256; (b) M. E. Jung and J. Pontillo, Org. Lett., 1999, 1, 367; (c) F.
Kido, T. Abiko and M. Kato, Bull. Chem. Soc. Jpn., 1992, 65, 2471;
(d) M. P. Doyle, V. Bagheri and E. E. Claxton, J. Chem. Soc., Chem.
Commun., 1990, 46; (e) P. A. Grieco, M. Meyers and R. S. Finkelhor, J.
Org. Chem., 1974, 39, 119; (f) G. Pourcelot;, L. Veniard and P. Cadiot,
Bull. Chem. Soc. Fr., 1975, 1281.
4 A. Fu¨rstner and P. W. Davies, Angew. Chem., Int. Ed., 2007, 46,
3410.
5 For reviews see: (a) Z. Li, C. Brouwer and C. He, J. Organomet. Chem.,
2006, 690, 4313; (b) H. V. R. Dias and C. J. Lovely, Chem. Rev.,
2008, 108, 3223; (c) Z. Li and C. He, Eur. J. Org. Chem., 2006, 19,
4313.
6 S. Bachmann, D. Fielenbach and K. A. Jorgenson, Org. Biomol. Chem.,
2004, 2, 3044.
7 J. L. Thompson and H. M. L. Davies, J. Am. Chem. Soc., 2007, 129,
6090.
8 H. Xu, W. Zhang, D. Shu, J. B. Werness and W. Tang, Angew. Chem.,
Int. Ed., 2008, 47, 8933.
9 X. Zhang, Z. Qu, Z. Ma, W. Shi, X. Jin and J. Wang, J. Org. Chem.,
2002, 67, 5621.
10 L. Peng, X. Zhang, M. Ma and J. Wang, Angew. Chem., Int. Ed., 2007,
46, 1905.
Pleasingly, the 2-bromoallyl unit underwent reaction to give the
desired product 4l in high yield (Entry 12).
Both aryl and benzyl substituted propargyl sulfides gave the
desired allenic products in high yield (Entries 13 and 14). The use
of these types of product in furan10 and pyrrole syntheses,11 led us
to also explore sulfide precursors bearing multiple alkene/alkyne
units in the reaction. The products are potentially valuable precur-
sors to sulfur heterocycles by further metal-promoted cyclisation
processes. Bispropargyl sulfide 3c and bisallyl sulfide 2m afforded
the 1,7-allen-yne system 5c and the 1,7-diene 4m respectively
in good yield. Allyl propargyl sulfide was assessed and gave a
mixture of products resulting from competing participation of
either the allyl or propargyl unit in the sigmatropic rearrangement
(Entry 17). A reasonable (4.9:1) preference was displayed for the
propargylic unit to undergo this process.
To further examine the scope of the silver catalysed process, allyl
ethers and amines were tested under the reaction conditions. To
date, none of the products expected from oxonium or ammonium
ylide formation have been observed.
11 L. Peng, X. Zhang, J. Ma, Z. Zhong and J. Wang, Org. Lett., 2007, 9,
1445.
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