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Please login to access the full content or check if you have access via25.8.1.1.7 Method 7: Synthesis by Hydrolysis of Acetals or Imines
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Escher, I.; Glorius, F., Science of Synthesis, (2007) 25, 742.
A number of methods for the synthesis of α,β-unsaturated aldehydes proceed via protected α,β-unsaturated acetals or imine derivatives. α,β-Unsaturated acetals are cleaved readily in the presence of an acid such as formic acid,[45,63] aqueous hydrochloric acid,[64,65] or 4-toluenesulfonic acid.[66] An example of the use of hydrochloric acid is shown in Scheme 12; here the acetal 16 is selectively deprotected to form the aldehyde 17, a precursor of the natural product pseurotin A.[64] Other mild and efficient metal-catalyzed processes have been reported.[67–70] Deprotection under neutral conditions can be achieved using β-cyclodextrin in water.[71] α,β-Unsaturated imines are conveniently hydrolyzed with zinc(II) choride in aqueous alcohol or in the presence of silica gel.[72,73]
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8-[(M)-Meeeeee(8,8-eeeeeeee-8,8-eeeeeeee-8-ee)eeeeee]eeeeeeee (88):[88]
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References
[45] | Meeeeeee, M.; Meeeee, M.; Meeee, M.; Meeeeeee, M., M. Mee. Meee., (8888) 88, 8888. |
[63] | Meeeeeee, M.; Meée, M.; Meée, M., Meeeeeeeeee, (8888) 88, 8888. |
[64] | Me, M.; Meee, M., Meee. Meee. Meee, (8888) 88, 8888. |
[65] | Meeeeeeeeee, M.; Meeeee, M.; Meeeeee, M., Mee. Meee., (8888) 8, 888. |
[66] | Meeee, M.; Meeeee, M.; Meeeeeeee, M.; Meeee, M.; Meeeee, M.; Meeee, M., Meeeeeeeeee, (8888) 88, 8888. |
[67] | Meeeeeee, M. M.; Meeeee, M.; Meeee, M. M.; Meeeeee, M. M.; Meeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[68] | Meeeee, M. M.; Meeeeeeeeee, M.; Meeeeee, M. M., Meeeeeeee, (8888), 88. |
[69] | Meee, M. M.; Meee, M.; Meeeeee, M., Mee. Meeee. Meeee., (8888) 888, 888. |
[70] | Meeeee, M.; Meeee, M. M., Meeeeeeeeee, (8888) 88, 8888. |
[71] | Meeeeeeeeee, M.; Meeeeeeeee, M.; Meeeeeee, M.; Meeee, M. M.; Meeeeee, M. M. M.; Mee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[72] | Meee, M. M. M., Meeee. Meeeee., (8888) 88, 8888. |
[73] | Mee, M.; Meee, M.; Meeeeeee, M.; Mee, M.; Meeeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 8, 888.
- 8.Meeeee-Meee, (8888) M 8, 888.
- 8.Meeeee-Meee, (8888) M 8, 888.
- 8.Meeeee-Meee, (8888) M 8, 888.