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Chiral Tetraaryl‐ and Tetraalkynylborates as Chiral Solvating Agents for Tetraalkylammonium Salts
Author(s) -
Tayama Eiji,
Sugawara Takeshi
Publication year - 2019
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.201801448
Subject(s) - chemistry , diastereomer , boron , chiral derivatizing agent , chirality (physics) , sodium salt , enantiomer , organic chemistry , inorganic chemistry , chiral column chromatography , chiral symmetry , physics , quantum mechanics , nambu–jona lasinio model , quark
The application of tetracarbon‐substituted chiral borate sodium salts (NaBR* 4 ) as NMR chiral solvating agents for various tetraalkylammonium salts (R 4 NX) has been successfully demonstrated. Ion exchange between R 4 NX and NaBR* 4 proceeded in excellent yields and provided the corresponding diastereomeric salts (R 4 NBR* 4 ). The ee values of the R 4 NX salts were determined by 1 H NMR analysis of R 4 NBR* 4 . Two types of chiral borates, tetraaryl‐ and tetraalkynylborates with optically active 1,1′‐binaphthyl components were used. At the beginning of this research, we investigated the efficacy of a known chiral tetraarylborate developed by Pommerening et al. for R 4 NX. To expand the possibility of further structural design of the chiral borate, we designed chiral tetraalkynylborates as a new structure. Their synthesis and application are also described.