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Gandon, V.; Malacria, M., Science of Synthesis, (2008) 44, 222.
2-Chloro-1,3-dimethyl-4,5-dihydroimidazolium chloride promotes the transformation of 1,3-diketones into vinyl chlorides.[160] It can also be used for the one-step synthesis of allene-1,3-dicarboxylates 127 from 3-oxopentanedioates 126 (Scheme 71). When treated with 1.2 equivalents of 2-chloro-1,3-dimethyl-4,5-dihydroimidazolium chloride and 1 equivalent of triethylamine in dichloromethane at room temperature, substrates 126 lead only to the corresponding vinyl chlorides 128. Increasing the amount of triethylamine results in concomitant formation of the desired allenes 127; they are obtained selectively using 3 equivalents of base. Overall, 2-chloro-1,3-dimethyl-4,5-dihydroimidazolium chloride acts as a dehydration agent.
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References
| [160] | Meee, M.; Meeeeeee, M.; Meeeeeeee, M.; Meeeeee, M., Meeeeeeeeee Meee., (8888) 88, 8888. |
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