85551-57-1Relevant articles and documents
Conformationally rigid chiral pyridine N-oxides as organocatalyst: Asymmetric allylation of aldehydes
Gnanamani, Elumalai,Someshwar, Nagamalla,Ramanathan, Chinnasamy Ramaraj
, p. 2101 - 2106 (2012)
A pyridine unit with a conformationally rigid chiral backbone has been designed and synthesized in an enantiomerically pure form to utilize in the Lewis base-catalyzed Sakurai-Hosomi-Denmark-type allylation reaction. The chiral pyridine N-oxide in 1:1 mix
Catalytic asymmetric synthesis of homoallylic alcohols: Chiral amplification and chiral poisoning in a titanium/BINOL catalyst system
Faller,Sams,Liu
, p. 1217 - 1218 (1996)
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Emergence of Highly Enantioselective Catalytic Activity in a Helical Polymer Mediated by Deracemization of Racemic Pendants
Ikai, Tomoyuki,Ando, Mitsuka,Ito, Masaki,Ishidate, Ryoma,Suzuki, Nozomu,Maeda, Katsuhiro,Yashima, Eiji
supporting information, p. 12725 - 12735 (2021/08/24)
Any polymers composed of racemic repeating units are obviously optically inactive and hence chiral functions, such as asymmetric catalysis, will not be expected at all. Contrary to such a preconceived notion, we report an unprecedented helical polymer-based highly enantioselective organocatalyst prepared by polymerization of a racemic monomer with no catalytic activity. Both the right- and left-handed helical poly(biarylylacetylene)s (PBAs) composed of dynamically racemic 2-arylpyridyl-N-oxide monomer units with N-oxide moieties located in the vicinity of the helical polymer backbone can be produced by noncovalent interaction with a chiral alcohol through deracemization of the biaryl pendants. The macromolecular helicity and the axial chirality induced in the PBAs are retained ("memorized") after complete removal of the chiral alcohol. Accordingly, the helical PBAs with dual static memory of the helicity and axial chirality show remarkable enantioselectivity (86% ee) for the asymmetric allylation of benzaldehyde. The enantioselectivity is slightly lower than that (96% ee) of the homochiral PBAs prepared from the corresponding enantiopure (R)- and (S)-monomers, but is comparable to that (88% ee) of the helical PBA composed of nonracemic monomers of ca. 60% ee.
Enantioselective Allylation of Oxocarbenium Ions Catalyzed by Bi(OAc)3/Chiral Phosphoric Acid
Cheng, Jin-Pei,Li, Xin,Pan, Yu-Liang,Wang, Jie,Yang, Chen,Zheng, Han-Liang
, p. 8069 - 8076 (2020/09/21)
Phthalides as the crucial core skeletons are found extensively in natural products and biological active molecules. Herein we disclose an asymmetric allylation of 3-hydroxyisobenzofuran-1(3H)-ones with boron allylation reagents to construct chiral phthali