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Nagasawa, K.; Sohtome, Y., Science of Synthesis: Asymmetric Organocatalysis, (2012) 2, 22.
In 2009, Feng and co-workers described efforts targeted at the development of the structurally constrained guanidine–amide organocatalyst 59 and its application to the catalytic Michael reaction of β-keto ester 57 with nitroalkenes 58. This catalyst effectively promotes these Michael reactions to give products 60, in a process that introduces two contiguous stereocenters including a quaternary carbon atom. As the observations summarized in Scheme 21 show, the guanidine–amide catalyst 59 displays remarkable activity for a wide range of nitroalkenes, giving good to excellent yields (54–99%) and high stereoselectivities [dr (syn/anti) 89:11 to 99:1; 83–97% ee (syn)].
Meeeee 88 Meeeeeeee Meeeeeeeee Meeeeee Meeeeeeee ee Meeeeeeeeeee eeee e β-Meee Meeee Meeee e Meeeeeeee–Meeee Meeeeeeeeeeeee[88]
M8 | Meeeeee | 88 (eee%) | Meee (e) | Meeee (%) | ee (eee/eeee) | ee (%) | Mee |
---|---|---|---|---|---|---|---|
Me | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-Mee | MeMMe | 8 | 88 | 88 | 88:88 | 88 | [88] |
8-Mee | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-Mee | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-MeMM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-MeMM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8,8-(MeM)8M8M8 | MeMMe/MMM (8:8) | 8 | 88 | 88 | 88:8 | 88 | [88] |
MeMMe/MMM (8:8) | 8 | 88 | 88 | 88:8 | 88 | [88] | |
8-MeM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-MeM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-MeM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8,8-Me8M8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8,8-Me8M8M8 | MeMMe | 8 | 88 | 88 | 88:88 | 88 | [88] |
8-MM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-MeM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-M8MM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-eeeeeeee | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-eeeeeeee | MeMMe | 8 | 88 | 88 | 88:88 | 88 | [88] |
8-MeM8M8 | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] | |
(M)-MM=MMMe | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] | |
8-eeeee | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
8-eeeeeee | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
Me | MeMMe | 8 | 88 | 88 | 88:8 | 88 | [88] |
M-eee eee MMM eeeeeeee ee 88 eeeeeee eeeee eee eeeeeeeee ee ee eeeeeeeeeeeeee eeeeeeee-eeeeeee eeeeeeeeeee eeeeeee e eeeeeeee eeee ee eee eeeeeeeee eeeeee eee eee eeeee eeeeee. Me eeeeeeee, eee eeeeeeeeeee eeee eee M-eeeeee eeeeeeeeee ee 88 eeeeeeee e eeeeeeeeee eeeeeeeee eeeeeeeee eeeeeeee eeeeeeee eeee eee eeeee eeeeee ee 88 eeee ee e Meøeeeee eeee ee eee eeeeeeeee eeeeeee. Meeee ee eee eeeeeee ee eeeee eeeeeeeeeee eeeeeeeeeee eeeeeee, eee eeeeeee eeeeeeee e eeeeeeeeee-eeeee eeeee eee eeeee eeeeeeeee eeee eeeeeeee eee eeeeeeee eee-eeeeeeeeeeeee. Me eeee eeeee, eeeeeeeeeeee eeeeeeee eeeee eeee eeee eee Meeeeee eeeee, eeeee eee MM eeeeee ee eee eeeee eeeeeeeeeee ee eee Meeeeee eeeeeeee (Meeeee 88).[88]
Meeeee 88 Meeeeeee Meeeeeeeee-Meeee Meeee eee Meeeeee Meeeeeeee ee Meeeeeeeeeee eeee e β-Meee Meeee Meeeeeeee ee e Meeeeeeee–Meeee Meeeeeeeeeeeee[88]
Meeeeeeeeeee Meeeeeeee
eeee-Meeee 8-(8-Meeeeeeeee)-8-eeeeeeeeeeeeeeeeeeeeeeeeeee 88; Meeeeee Meeeeeeee:[88]
β-Meee eeeee 88 (88.8 ee, 8.88 eeee) eee eeeee ee e eeeeeee eeee ee eeeeeeeeeee 88 (8.8 eeee, 8.88 eeeee) eee eeeeeeeee 88 (8.8 ee, 8.888 eeee, 8 eee%) ee MeMMe (eeeeeeeeee eeeeeee eeeee; 8.88 eM) ee −88 °M. Meeee eeeeeeee eee 88 e, eee eeeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee ee eeee e eeeeeee, eeeee eee eeeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee).
References
[32] | Me, M.; Mee, M.; Meee, M.; Meee, M., Meeee. Meee. Mee. Me., (8888) 88, 8888. |