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Colonna, S.; Perdicchia, D., Science of Synthesis: Stereoselective Synthesis, (2011) 1, 134.
Another additive that has a remarkable effect on the enantioselectivity of chiral lanthanum complex catalyzed asymmetric epoxidations of enones is triphenylphosphine oxide.[40] When added in amounts of 15–30 mol%, it enhances the degree of asymmetric induction in the epoxidation of (E)-1,3-diphenylprop-2-en-1-one (8) by tert-butyl hydroperoxide in the presence of 5 mol% of lanthanum–(R)-BINOL to 96% ee. Similar high enantiomeric excesses are obtained for three alkyl ketones (Scheme 15). Furthermore, all the reagents are commercially available, making this procedure highly practical.
Meeeee 88 Meeeeeee ee Meeeeeeeeee eeee Meeeeeeeeeeeeeeeee Meeee ee ee Meeeeeee[88]
M eeeeeeeeee eeeeeeee eeeeeeeee eeeeee (eeeeeeeeee eeeeeeeeeeeee) eeeeee eeee eeee(8-eeeeeeeeeeee)eeeeeeeee eeeee ee eeee ee eee eeeeeeee, eee e eeeeeee ee eeeeeeeeee eeeeee 88 eee ee eeeeeeeeee ee eee eeeeeeeeeeeee eeeeeeee 88 eeee eeeeeeeee eeeeeeeeeeeeeeeeeeee (ee ee 88% ee) (Meeeee 88).[88]
Meeeee 88 Meeeeeeeee Meeeeeeeeee ee Meeeeeeeee Meeeee Meeeeeeee ee e Meeeee Meeeeeeee–8,8′-Me-8-eeeeeeee–Meeeeeeeeeeeeeee Meeee Meeeeee[88]
M8 | M8 | Me8 | Meee (e) | Meeee (%) | ee (%) | Mee |
---|---|---|---|---|---|---|
Me | Me | Me | 88 | 88 | >88 | [88] |
Me | eMe | Me | 88 | 88 | >88 | [88] |
eMe | Me | Me | 88 | 88 | 88 | [88] |
Me | Me | 8-MM8M8 | 88 | 88 | 88 | [88] |
Me | 8-MeMM8M8 | 8-MM8M8 | 88 | 88 | 88 | [88] |
Me | eMe | 8-MM8M8 | 888 | 88 | >88 | [88] |
Me | e-Me | 8-MM8M8 | 88 | 88 | >88 | [88] |
8-MeMM8M8 | Me | 8-MM8M8 | 88 | 88 | >88 | [88] |
8,8-(MeM)8M8M8 | Me | 8-MM8M8 | 88 | 88 | >88 | [88] |
8-MMM8M8 | Me | 8-MM8M8 | 88 | 88 | >88 | [88] |
8-M8MM8M8 | Me | 8-MM8M8 | 88 | 88 | >88 | [88] |
eMe | Me | 8-MM8M8 | 88 | 88 | 88 | [88] |
8-MM8M8 | e-Me | 8-MM8M8 | 88 | 88 | 88 | [88] |
Me | Me | 8-MM8M8 | 888 | 88 | 88 | [88] |
MM8Me | Me | 8-MM8M8 | 888 | 88 | 88 | [88] |
Meeeeeeeeeeeeeee ee Meeeeeeeeʼe eeeeeeeee eeeeeeee ee eeeee eeeeeeeeee MMMMM eeeeeee eeeeeee ee eeeeeee ee eeeeeee eeeeee eee eeeee, e.e. 88 (Meeeee 88), eee eeee eeeeeeee.[88] Mee eeeeeeee eee eeeeeeee ee eeeeeeee eeeeeeee ee eeeeee 88 ee eeeeeeeeeeeeeee eee eeeeeeeeeeeeeeeeee eeeee ee e eeeeeeee ee eeeeeeeee(MMM) eeeeeeeeeeee eeeee eeeee. Meee eeee eeeeeeee ee eeee eeee eeeeee eeeeeeeeeeeee (8.8 eeeee) ee eeeeeeeeeeeeeee ee eeeeeeeee (M)-8,8-eeeeeeeeeeee-8-ee-8-eee (88, M8 = M8 = Me) ee e eeeee eeeeeeeee eeeee eeeeeeeeeee eeeeeeeeee, eee eeeeeeeeeeeee (M,M)-eeeeeee 88 ee eeeeeeee ee eeee eeee 88% eeeee eee 88.8% ee eeeee e eeeeeeee eeee ee 88 eeeeeee. Mee eeeeeeee ee eeeeeeeee eeeeee (8 Å) ee eeeeeeeee ee eeeee ee eee eeeeeeeee eeeeeeee. Meee eee eeeeee eee eee eeeeeee eeeeeeeeeee ee eee eeeeeee eee eeeeeee eee eee eeeeeeeeeeeeeeeeee ee eee eeeeeeeeeee. Meeeeeeee eeeeeee ee eeeee ee eeeeeeeeeeeeeeeeee eee eeeeeeee eeeee eee ee eeeeeeee eeee e eeeeeee ee α,β-eeeeeeeeeee eeeeeee (Meeeee 88), eeeeeeee eee eeeeeeee ee eeeeeeee-eeeeeeeeeee eeeeee ee eee eeee-eeeeeeee eeeeeee eee eeeeeeeeee ee, ee eeee eeeeee, eeee eee eee ee eeeee-eeeeeeeeeee α,β-eeeeeeeeeee eeeeeee.
Meeeee 88 Meeeeeeeeeeeeeee Meeeeeeeeee ee α,β-Meeeeeeeeee Meeeeee Meeeeeeee ee e Meee-Meeeeeeee Meeeeeee[88]
M8 | M8 | Meee (e) | Meeee (%) | ee (%) | Mee |
---|---|---|---|---|---|
Me | Me | 8.8 | >88 | 88 | [88] |
8-MM8M8 | Me | 8.8 | >88 | 88 | [88] |
8-MeM8M8 | Me | 8.8 | >88 | 88 | [88] |
8-MeM8M8 | Me | 8.8 | >88 | 88 | [88] |
8-M8MM8M8 | Me | 8 | >88 | 88 | [88] |
8-MMM8M8 | Me | 8 | >88 | 88 | [88] |
Me | 8-MeMM8M8 | 8.8 | >88 | 88 | [88] |
eMe | Me | 8 | 88 | 88 | [88] |
Mee eeeeeeeeee eeeeeeeee ee eee eeeeeeeeeeeee eeeeeeee eeee eee eeeeeeeeee eeeeeeeeeee ee eee eeee ee eeeeeeee eee eeeeeeeee ee eee eeeeeeeeeee ee eee eeeee eeeeeeeee. Me eeeee ee Meeee 8 eee eeeeeeee eee ee eeee eee ee eeeee eee eeeeee ee eee eeeeeeeeeee ee (M)-8,8-eeeeeeeeeeee-8-ee-8-eee (88, M8 = M8 =Me) eeeeeee e eeeeee eeee ee eeeeeeeeeeeeeeeeee.[88]
Meeee 8 Meeeeeeee eee Meeee ee eee Meeeeeeeeeeee Meeeeeee ee eee Meeeeeeeeeeeeeee Meeeeeeeeee ee (M)-8,8-Meeeeeeeeeee-8-ee-8-eee[88]
Mee | Me8MM (eee%) | Meee (e) | Meeee (%) | ee (%) | Mee |
---|---|---|---|---|---|
8 | 88 | 8.8 | >88 | 88.8 | [88] |
8 | 88 | 8.8 | >88 | 88.8 | [88] |
8 | 88 | 8.8 | >88 | 88.8 | [88] |
8 | 88 | 8.8 | >88 | 88.8 | [88] |
8 | 88 | 8.8 | 88 | 88.8 | [88] |
8 | 88 | 8 | 88 | 88.8 | [88] |
Meeeeeeeeeee Meeeeeeee
(8M,8M)-8,8-Meeeeeee-8-(8-eeeeeeeeeeee-8-ee)eeeeee-8-eee (88, M8 = Me; M8 = e-Me); Meeeeee Meeeeeeee:[88]
MMMMMMM: Me ee eeeeeeee eeeeeeeeeee eeee eeeeee eeeeeeee eeeeee ee eeeeeeeee ee eee eee ee eee eeeeeeee eeeeee eeeeeee eeeeee.
M eeee ee (M)-MMMMM (8.8 ee, 8.88 eeee) eee eeee(8-eeeeeeeeeeee)eeeeeeeee eeeee (88.8 ee, 8.88 eeee) ee eee MMM (8 eM) eee eeeee ee e eeeeeee ee Me(MeMe)8 (8.8 ee, 8.88 eeee) eee eeee-eeeee 8-Å eeeeeeeee eeeeee (88 ee) eeeee eeeee, eee eee eeeeeee eee eeeeeee ee ee eee 8 e. Meeeee eeeeeeeeeeeee (8.8 ee, 8.88 eeee) eee eeeee eee eee eeeeeee eee eeeeeee eee 88 eee. M eeee ee (M)-8,8-eeeeeeee-8-eeeeeeeeee-8-ee-8-eee (88, M8 = Me; M8 = e-Me; 88.8 ee, 8.8 eeee) ee MMM (8 eM) eee eeee eeeee, eeeeeeee ee eeeeeeee eeeeeeee ee eeeeee eeeeeeeeeeeee (88.8 ee, 8.88 eeee) eeee 88 eee. Mee eeeeeee eee eeeeeee eee e eeeeeee 88 eee eeee eeeeee eee (~888 ee) eee eeeee, eee eee eeeeeee eee eeeeeeee eeeeeee Meeeee. Mee eeeeeeee eee eeeeeeeeeeee eee eee eeeeeee eee eeeeee eeeeeee e eeeee eeeeee ee eeeeee eee (M)-MMMMM (MM-eeeeee eee, eeeeee/MeMMe 8:8). Mee eeeee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee); eeeee: 88% eeeee; >88% ee.
References
[40] | Meeeee, M.; Meeeeee, M.; Meeeeee, M., Meeeeeeeeee Meee., (8888) 88, 8888. |
[41] | Meee, M.; Meeeee, M.; Meeeeeee, M.; Meeeee, M.; Meeeeee, M., Mee. Meeeee. Meee., (8888) 8, 8888. |
[42] | Meee, M.; Mee, M.; Me, M.; Meee, M., Meeee. Meee., (8888) 888, 8888; Meeee. Meee. Mee. Me. Meee., (8888) 88, 8888. |