97550-63-5Relevant academic research and scientific papers
2,8'-Disubstituted-1,1'-Binaphthyls: A New Pattern in Chiral Ligands
Vyskocil, Stepan,Meca, Ludek,Tislerova, Iva,Cisarova, Ivana,Polasek, Miroslav,Harutyunyan, Syuzanna R.,Belokon, Yuri N.,Stead, Russel M. J.,Farrugia, Louis,Lockhart, Stephen C.,Mitchell, William L.,Kocovsky, Pavel
, p. 4633 - 4648 (2007/10/03)
The title binaphthyls 19 and 26, which are the positional isomers of 2-methoxy-2'-(diphenylphosphino)-1,1'-binaphthyl (MOP, 19) and 2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN, 26), have been synthesized by Suzuki coupling as the key step (10 + 15 -> 18), followed by functional group transformations, involving C-P and C-N bond formation (18 -> 19 and 18 -> 23). Racemic intermediate 22 was resolved by cocrystallization with N-benzylcinchonidinium chloride and the absolute configuration determined by X-ray crystallography. These novel binaphthyls are configurationally stable and, as such, potentially usable as chiral ligands in asymmetric reactions. Michael addition of the glycine-derived enolate 40 to methyl acrylate, carried out in the presence of (R)-(-)-27 as the chiral phase-transfer catalyst, afforded L-glutamic acid (S)-(+)-43 of 92% ee (after hydrolysis of the primary product).
