Synthesis
Since the 1970s, the synthesis and resolution of racemic 2-amino-2'-hydroxy-1,1'-binaphthylene, as well as its asymmetric synthesis, have received increasing attention. Racemic 2-amino-2'-hydroxy-1,1'-binaphthylene is primarily obtained through oxidative coupling with 2-naphthol and 2-naphthylamine, while optically active compounds are often obtained through resolution methods. Resolution of these compounds can be achieved through biological or chemical methods. Chemical resolution utilizes the functional group characteristics of 2-amino-2'-hydroxy-1,1'-binaphthylene, reacting it with a photoactive reagent to obtain diastereomers, which are then purified and decomposed using their differences in properties to obtain the photoactive product. In addition, enzymatic and chromatographic methods are also used for resolution. Numerous studies and reviews have been conducted on the resolution of 2-amino-2'-hydroxy-1,1'-binaphthylene. The synthesis of 2-amino-2'-hydroxy-1,1'-binaphthyl is almost always obtained by oxidizing 2-naphthol and 2-naphthylamine with suitable oxidants. The synthetic reaction formula for (S)-2'-Amino-1,1'-binaphthalen-2-ol is shown in the figure below:
Figure 1 Synthetic reaction formula for (S)-2'-Amino-1,1'-binaphthalen-2-ol
Uses
(
S)-(-)-2′-Amino-1,1′-binaphthalen-2-ol or (
S)-NOBIN, is a non-symmetrically substituted 1,1′-binaphthalene ligand. It can be used as a catalyst in the asymmetric synthesis of unnatural α-alkyl amino acids by phase-transfer catalysis (PTC). (
S)-NOBIN can also be employed as starting material to prepare
N-monoalkyl and
N,
N-dialkyl (
S)-NOBIN analogs by reacting with aldehydes via reductive amination reaction.
N-monoaryl derivatives are obtained from NOBIN via HartwigBuchwald arylation reaction.
