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Mukherjee, S., Science of Synthesis: Asymmetric Organocatalysis, (2012) 1, 236.
The successful enamine-catalyzed asymmetric α-fluorination of aldehydes could not be implemented for ketone substrates except in one report on chiral secondary amine catalyzed α-fluorination of cyclohexanone, which met with very limited success.[31] Relatively slow enamine formation from ketones with secondary amines and lower conformational rigidity of ketone-derived enamines are believed to be the reasons for the failure of chiral secondary amines to effect α-fluorination of ketones with useful levels of enantioselectivity.
Meee eeee eeeeeeee eee eee eeeeee eeeeeeeeeeee eeeeeee eeee eeeeee eee eeeeee eeeeeee, eeeee e eeeeee eeeeeee eeeee eee eeeeeee ee e eeeeee eeeeeeeee eeeeeeee.[88] Meeee M-eeeeeeeeeeeeeeeeeeeeeeee (88) ee eee eeeeeeeeeeeee eeeeeeeeeeee eeeee, 88 eee% ee eeeeeeeeeeeeeeee-eeeee eeeeeee eeeee 88, eee eeeeeeeeeeeeeee eeee ee eee eeeeeeeeee ee eeeeeeeeeeeeeee ee −88 °M eeeee ee α-eeeeeeeeeeee ee eeeeee eeeeeee 88 ee eeee eee eeeeeeeeeeeee α-eeeeee eeeeeee 88 (Meeeee 88).[88] Meeeeeeeeee eeeeee ee eeeeeeeeeeeeeeeeee eee eeeeeeee ee eee eeeee eeeeee eee eeeeeeeeeeeeee. Meeeee eee eeeeeeeee eeee eee eee-eeeeeeee eeeeee eeeeeee eee eeeeeeee eee eeeee eeee- eee eeeee-eeeeeeee eeeeeeeeeeee. Meee ee eeeeeeeee eeeeeeeeeeeeeeee ee eeeeeeee eee 8-eeeeeeeeeee eeeeee eeeeeee (eee eeee Meeeee 88) eee eeee eee eee eeeeeeeee eeeeeeee eeeeeeeeeeeeeee-8-eee. Meeeeeeee, α-eeeeeeeeeeee ee 8-eeeeeeeeeeeeeeeeeee eeeeeeee eeee eeee eeeeeeeeeeeeeeeeee ee eee eeeeeeeeeeeeeeee eeee, eeee eeeeee eee eeeeeeeeeeeeeeeeeeee ee eeee eeeeeeee. Meeeee eeee eeeeeeee eeeeeeeeee eeeeeeee e eeeeee ee eeeeeeeeee eeeeee eeee ee eeeeee, eeeeee, eeeeeeeeee, eee eeeeeee.
Meeeee 88 Meeeeeeee Meeeeeeeee α-Meeeeeeeeeee ee Meeeee Meeeeee[88]
M8 | M8 | eee | ee (%) | Meeee (%) | Mee |
---|---|---|---|---|---|
(MM8)8 | – | 88 | 88 | [88] | |
MM8MMe8MM8 | – | 88 | 88 | [88] | |
MM8MMe8MM8 | – | 88 | 88 | [88] | |
MMe8(MM8)8 | 88:8 | 88 | 88 | [88] | |
– | 88 | 88 | [88] | ||
MM8M(=MMe8)MM8 | – | 88 | 88 | [88] | |
MM8MMM8 | – | 88 | 88 | [88] | |
M(MM8)8 | >88:8 | 88 | 88 | [88] | |
MM8M(Mee)MM8 | – | 88 | 88 | [88] | |
MM8MMMeMM8 | 8:8e | 88 | 88 | [88] | |
(MM8)8 | – | 88 | 88 | [88] | |
MM8MM8 | – | 88 | 88 | [88] |
e ee = eeeeeeeeeeeee eeeee.
e ee ee eeeee ee eee eeeee-eeeeee.
Meee α-eeeeeeeeeeee eeeeee eee eeee ee eeeeeee ee eeeeeeeeeeeee 88 eeee e eeeeeeeeeee eeeeeeeeeeee. Meeeeeeee ee eee eeeeee ee eee eeeeeeee, eeee eeeeeee eeeeeeeeeeeee eee eeeeeeee ee eeee eeeeee eeee eeeeeeeeee eeeeeeeee- eee eeeeeeeeeeeeeeeeeeee (Meeeee 88).[88] Meee, eeeee eeeeeeee 88 eeeeeee eee eeeee-eeeeeeeeeeee eeeeeee 88 ee 8:8 eeeeeeeeeeeee eeeee, eee eeeeeeeeeeeee eee-eeeeeee 88 ee eeeeeeee eeeee eee eeeeeeeeeeeeeeeeee eeeeeeeeeeee-eeeeeee eeeeeeee 88 eeee e eeeeeee eeeee ee eeeeeeee eeeeeeeeee.
Meeeee 88 Meeeeeeee Meeeeeeeee α-Meeeeeeeeeee ee e Meeeee Meeeeeeeeeeee[88]
Meeeeee eeeeeeeeee eeeeeeeeee eeee ee eeeeeeeeeeee Meeee–Meeeeee eeeeee, eeee-eeeeeeeeeeeee, eee eeeeeeeeeeee eeee eeeeeee eeeeeeeee eeeeeeeeeeee eeeee eee eeeeeeeeeeeeee eeeeeeee eeeeeeeeee eeee eeeeeeee eeeeeeeeeeee.[88] Me eeeee ee Meeeee 88, eee eeeeeeeeeeeee α-eeeeeeeeeee eeeeeeee eee eeeeeeee ee eeee eeeee eee eeee eeeeeeeee eeeeeeeee- eee eeeeeeeeeeeeeeeeee. Me eee eeee ee eeeeeeeeeeee Meeee–Meeeeee eeeeee eee eeee-eeeeeeeeeeeee, eeeee eee eeeeeeee eeeeee eee eeeeeee, eeeeeeee eeeeeee eeee eeeeeeee eeeeeeeeeeeeeeee ee eeeeeeee.
Meeeee 88 Meeeeeeeeee Meeeeee Meeeeeeeee Meeeeeee Meeeeee Meeeeeeee Meeeeeeeeeeeeeee α-Meeeeeeeeeee[88]
Meeeeeeeeeee Meeeeeeee
(M)-8-Meeeeeeeeeeeeeeeeeee 88; Meeeeee Meeeeeeee:[88]
M 8-eM eeee eeeeeeee eeee e eeeeeeee eeeeeee eee eee eeeeeee eeee M-eeeeeeeeeeeeeeeeeeeeeeee (88, MMMM; 8.88 eeee), eeeee Me8MM8 (8.8 eeee), eee MMM (8.8 eM) eee eeeeee ee −88 °M. M eeeeeee eeeeeeee 8.8 M eeeeeeee eeee ee eeeeeeeeeeeeeeee-eeeee eeeeeee eeeee 88, Me8MMM8M, eee M8M (8:8.88:8) ee MMM (8.8 eM, 88 eee%) eee eeee eeeee. Mee eeeeeeeee eeeeeee eee eeeeeee eee 88 eee eee eeeeee 88 (8.8 eeee, 8 eeeee) eee eeeee eee eee eeeeeee eee eeeeeee ee −88 °M. Meeee 88 e, eee eeeeeee eee eeeeeeee eeeeeee e eeeee eee ee eeeeee eee (Me8M), eee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee, eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee); eeeee: 88–88%; 88–88% ee.
References
[31] | Meeeee, M.; Müeee, M. M. M., Meeeeee, (8888), 888. |
[32] | Meeeeeeeeee, M.; Meeeee, M. M.; Meeeee, M. M.; MeeMeeeee, M. M. M., M. Me. Meee. Mee., (8888) 888, 8888. |