Organocatalyzed enantioselective desymmetrization of aziridines and epoxides
- Ping-An Wang
Beilstein J. Org. Chem. 2013, 9, 1677–1695, doi:10.3762/bjoc.9.192
Graphical Abstract
Figure 1: The catalyzed enantioselective desymmetrization.
Figure 2: Cinchona alkaloid-derived catalysts OC-1 to OC-11.
Scheme 1: The enantioselective desymmetrization of meso-aziridines in the presence of selected Cinchona alkal...
Figure 3: Cinchona alkaloid-derived catalysts OC-12 to OC-19.
Scheme 2: The enantioselective ring-opening of aziridines in the presence of OC-16.
Scheme 3: OC-16 catalyzed enantioselective ring-opening of aziridines.
Figure 4: The chiral phosphoric acids catalysts OC-20 and OC-21.
Scheme 4: OC-20 and OC-21 catalyzed enantioselective desymmetrization of meso-aziridines.
Figure 5: The proposed mechanism for chiral phosphorous acid-induced enantioselctive desymmetrization of meso...
Scheme 5: OC-21 catalyzed enantioselective desymmetrization of meso-aziridines by Me3SiSPh.
Scheme 6: OC-21 catalyzed the enantioselective desymmetrization of meso-aziridines by Me3SiSePh/PhSeH.
Figure 6: L-Proline and its derivatives OC-22 to OC-27.
Scheme 7: OC-23 catalyzed enantioselective desymmetrization of meso-aziridines.
Figure 7: Proposed bifunctional mode of action of OC-23.
Figure 8: The chiral thioureas OC-28 to OC-44 for the desymmetrization of meso-aziridines.
Scheme 8: Desymmetrization of meso-aziridines with OC-41.
Figure 9: The chiral guanidines (OC-45 to OC-48).
Scheme 9: OC-46 catalyzed desymmetrization of meso-aziridines by arylthiols.
Scheme 10: Desymmetrization of cis-aziridine-2,3-dicarboxylate.
Figure 10: The proposed activation mode of OC-46.
Scheme 11: The enantioselective desymmetrization of meso-aziridines by amine/CS2 in the presence of OC-46.
Figure 11: The chiral 1,2,3-triazolium chlorides OC-49 to OC-55.
Scheme 12: The enantioselective desymmetrization of meso-aziridines by Me3SiX (X = Cl or Br) in the presence o...
Figure 12: Early organocatalysts for enantioselective desymmetrization of meso-epoxides.
Scheme 13: Attempts of enantioselective desymmetrization of meso-epoxides in the presence of OC-58 or OC-60.
Scheme 14: The enantioselective desymmetrization of a meso-epoxide containing one P atom.
Figure 13: Some chiral phosphoramide and chiral phosphine oxides.
Scheme 15: OC-62 catalyzed enantioselective desymmetrization of meso-epoxides by SiCl4.
Figure 14: The proposed mechanism of the chiral HMPA-catalyzed desymmetrization of meso-epoxides.
Scheme 16: The enantioselective desymmetrization of meso-epoxides in the presence of OC-63.
Figure 15: The Chiral phosphine oxides (OC-70 to OC-77) based on an allene backbone.
Scheme 17: OC-73 catalyzed enantioselective desymmetrization of meso-epoxides by SiCl4.
Figure 16: Chiral pyridine N-oxides used in enantioselective desymmetrization of meso-epoxides.
Scheme 18: Catalyzed enantioselective desymmetrization of meso-epoxides in the presence of OC-80 or OC-82.
Figure 17: Chiral pyridine N-oxides OC-85 to OC-94.
Scheme 19: Enantioselective desymmetrization of cis-stilbene oxide by using OC-85 to OC-92 as catalysts.
Figure 18: A novel family of helical chiral pyridine N-oxides OC-95 to OC-97.
Scheme 20: Desymmetrization of meso-epoxides catalyzed by OC-95 to OC-97.
Scheme 21: OC-98 catalyzed enantioselective desymmetrization of meso-epoxides by SiCl4.
One-pot tandem cyclization of enantiopure asymmetric cis-2,5-disubstituted pyrrolidines: Facile access to chiral 10-heteroazatriquinanes
- Ping-An Wang,
- Sheng-Yong Zhang and
- Henri B. Kagan
Beilstein J. Org. Chem. 2013, 9, 265–269, doi:10.3762/bjoc.9.32
Graphical Abstract
Figure 1: The structures of azatriquinanes and azatriquinacene.
Figure 2: The synthesis of 4 (previous work).
Scheme 1: The designed synthetic route to a hydroxy NHC from 4b.
Scheme 2: The reduction of amides 4 by LiAlH4 and BH3·THF.
Figure 3: X-ray crystal structure of compound 5a.
Scheme 3: One-pot tandem cyclization of 6 in the presence of HC(OCH3)3.
Figure 4: X-ray crystal structure of compound 7b.
Figure 5: The structural comparison of chiral ammonium salts such as 7 with the chiral PTCs of Denmark et al.
