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Murphy, P. J., Science of Synthesis, (2003) 14, 863.
It has been reported[19–22] that reaction of benzeneselenols with either β-oxo esters or malonic acid derivatives in the presence of a strong acid (a Simonis-type reaction) leads to 1-benzoselenopyran-4-ones and/or 1-benzoselenopyran-2-ones. For example, reaction of the substituted benzeneselenols 30 with β-oxo esters 31 or diketene 32 leads to the 4H-1-benzoselenopyran-4-ones 33; however, the yields are always low (Scheme 11).[19,20] Similarly, reaction of the benzeneselenols 34 with malonic acids 35 leads to the 4-hydroxy-2H-1-benzoselenopyran-2-ones 36; again, the yields for this process are poor.[21] A slightly different reaction occurs when the malonic esters 37 are utilized in this reaction, in that the 2-(phenylselanyl)-4H-1-benzoselenopyran-4-ones 38 are obtained in 20–30% yield (Scheme 11).[22]
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References
[19] | Meeee, M.; Meeeee, M., Meee. Mee. Meee. Meee., (8888) 88, 888. |
[20] | Meeee, M.; Meeee, M.; Meeeee, M., Meee. Mee. Meee. Meee., (8888) 88, 88. |
[21] | Meeee, M.; Meeeeee, M.; Meeeee, M., Meee. Mee. Meee. Meee., (8888) 88, 888. |
[22] | Meeee, M.; Meeeeeee, M.; Meeeee, M., Meee. Mee. Meee. Meee., (8888) 88, 888. |