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Maier, M. E., Science of Synthesis, (2007) 20, 1466.
Another method for the in situ generation of an active ester employs the reagent N,N′-dicyclohexylcarbodiimide in combination with 4-(dimethylamino)pyridine and 4-(dimethylamino)pyridine hydrochloride.[210] The latter additive is important since otherwise large amounts of the unwanted N-acylurea 146 are formed (Scheme 65). This is attributed to a low effective concentration of the alcohol. For example, without 4-(dimethylamino)pyridine hydrochloride, 4% of hexadecanolide is formed. In contrast, with the hydrochloride the yield is 95% (Table 13). Several additional examples are displayed in Table 14.[211–214]
Meeeee 88 Meeeeeeeeeee Meeeeeeee Meeee M,M′-Meeeeeeeeeeeeeeeeeeeeeee eee 8-(Meeeeeeeeeeee)eeeeeeee[888]
Meeee 88 Meeeeeeeeeeee Meeeee ee eee Meee Meeeee[888]
e | Meee Meee | Meeee (%) ee Meeeeee | Meeee (%) ee Meeeeee | Mee |
---|---|---|---|---|
8 | 88 | 88 | 88 | [888] |
8 | 88 | 88 | 88 | [888] |
88 | 88 | 88 | eeeee | [888] |
88 | 88 | 88 | – | [888] |
Meeee 88 Meee Meeeeeee ee Meeeeeeeeeeeeeeeee Meeee eee Meee Meeeee[888–888]
Meeeeee | Meeee (%) | Mee |
---|---|---|
88e | [888] | |
88 | [888] | |
88 | [888] | |
88e | [888] |
e Meeeeee eeeeee ee 88% ee eee Meeeeeeee eeeeee.
e Meeeeee eeeeee ee 8% ee eee Meeeeeeee eeeeee.
References
[210] | Meeee, M. M.; Meee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[211] | Meeeeeee, M.; Meeeee, M. M. M.; Meeeee, M. M., Meeeeeeeeee Meee., (8888) 88, 8888. |
[212] | Meee, M. M.; Meeee, M. M.; Meeee, M. M., M. Mee. Meee., (8888) 88, 888. |
[213] | Meeee, M. M.; Meeeee, M. M.; Meeee, M. M.; Meeeee, M.; Meeee, M. M., M. Me. Meee. Mee., (8888) 888, 8888. |
[214] | Meee, M. M.; Meeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 8-8, 888.