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Ar‐BINMOLs with Axial and sp 3 Central Chirality – Characterization, Chiroptical Properties, and Application in Asymmetric Catalysis
Author(s) -
Gao Guang,
Bai XingFeng,
Yang HuaMeng,
Jiang JianXiong,
Lai GuoQiao,
Xu LiWen
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201100664
Subject(s) - chemistry , diethylzinc , supramolecular chemistry , chirality (physics) , adduct , supramolecular chirality , differential scanning calorimetry , monomer , stereochemistry , catalysis , molecule , crystallography , enantioselective synthesis , organic chemistry , polymer , chiral symmetry breaking , physics , quantum mechanics , quark , nambu–jona lasinio model , thermodynamics
2′‐Hydroxy‐1,1′‐binaphthalene‐2‐(arylmethanol) (Ar‐BINMOLs), a family of new 1,1′‐binaphthalene‐2,2′‐diol derivatives, prepared by a [1,2]‐Wittig rearrangement, are introduced as new chiral molecules for the study of the modes of supramolecular aggregation on the basis of ESI‐MS, NMR spectroscopy, differential scanning calorimetry (DSC), and X‐ray diffractometry. Characterization showed that Ar‐BINMOLs exhibit different characteristics to BINOL and act as supramolecules due to hydrogen bonding and aromatic π–π/C–H ··· π interactions. In particular, CD measurements of chiral and racemic Ar‐BINMOL 2a in solution and the solid state show a strong Cotton effect, which revealed that amplification of chirality was observed because of the formation of a chiral supramolecular oligomer derived from the racemic monomer. To this end, the Ar‐BINMOLs were used as supramolecular auxiliaries to mediate the Michael reaction of anthrone to ( E )‐β‐nitrostyrene and could give the Michael adduct with comparable enantioselectivities. In addition, the Ar‐BINMOLs act as ligands to promote asymmetric 1,2‐addition of diethylzinc to aldehydes, which resulted in excellent yields and enantioselectivities (up to >99.9 % ee ) in the reactions of diethylzinc with a broad range of aromatic aldehdyes.