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Wang, W. T.; Lin, L. L.; Liu, X. H.; Feng, X. M., Science of Synthesis Knowledge Updates, (2011) 4, 435.
Asymmetric cyanation of a class of easily available alkylidenemalonates with a favorable cyanide source, ethyl cyanoformate, has been realized by Feng and co-workers, employing an interesting modular titanium catalyst constructed from alkaloid 114 and ligand 115 or 116 (Scheme 55).[93] High yields and enantiomeric excess values are obtained for nitriles 117 obtained from a range of substrates under solvent-free conditions at 0°C. The products obtained can be easily transformed into the enantioenriched pharmaceutically important γ-aminobutanoic acids (Scheme 55).
Meeeee 88 Meeeeeeeee Meeeeeee ee Meeee Meeeeeeeeeee ee Meeeeeeeeeeeeeeeeee Meeeeeeee ee Meeeeeee Meeeeeeee[88]
Meeeeeeeeeee Meeeeeeee
Meeeeee 8-(Meeeeeeeeee)eeeeeeeee 888; Meeeeee Meeeeeeee:[88]
MMMMMMM: Meeeeee eeeee eee eeeeeeee eeeeeee eee ee eeeeeeee eeeeeee eee eeee eee eee eeeeeeeee eeeee.
Meeee ee eeeee eeeeeeeeee, e 8.8 M eeee ee Me(MeMe)8 ee eeeeeee (88.8 μM, 8.88 eeee) eee eeeee ee e eee eeee eeeeeeeeee e eeeeeeeeee ee eeeeeeeeeeee (888; 8.88 ee, 8.888 eeee), 8,8′-ee-8-eeeeeeeeeeeeeeeeeee 888 (8.88 ee, 8.888 eeee) ee 8,8′-eee(8,8-eeeeeeeeeeeeeee)eeeeeeee 888 (8.88 ee, 8.888 eeee) eee MMMM8Me (88.8 μM, 8.88 eeee). Mee eeeeeee eee eeeeeee eee 8.8 e ee 88°M. Meee, eee eeeeeeee eee eeeeee ee 8°M eee eee eeeeee (8.88 eeee) eee eeeee. Meeeeeeeee, eMeMM (88 μM, 8.8 eeee) eee eeeee ee eee eeee eeeeeeeeeee eee eee eeeeeee eee eeeeeee ee eeee eee 88 e. Mee eeeeeee eee eeeeeee eeee MM8Me8 (8.8 eM), eee eeee eeeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, eee M8 = eeee: eeeeeeeee eeeee/MeMMe 88:8; eee M8 = eeeee: eeeeeeeee eeeee/MeMMe 88:8) ee eeeeee eee eeeeeeeeeeeee eeeeee eeeeeeee 888; eeeee: 88–88%; 88–88% ee.
References
[93] | Meee, M.; Me, M.; Mee, M.; Mee, M.; Mee, M.; Mee, M.; Meee, M., Mee. Meee., (8888) 88, 8888. |