A Facile Synthesis of 2-Amino-2′-hydroxy-1,1′-binaphthyl and 2,2′-Diamino-1,1′-binaphthyl by Oxidative Coupling Using Copper(II) Chloride

Synthesis of NOBIN Derivatives for Asymmetric Catalysis

“…Zhang and coworkers recently reported a Bucherer amination strategy using BINOL as the starting material [5]. The reaction was carried out under very harsh conditions (200°C, 5 days in autoclave) to afford NOBIN in 91% isolated yield without detectable amount of BINAM (2). A significant improvement for the practical synthesis of racemic NOBIN (3) was achieved in our group (scheme 1) [7].…”

“…However, [(±)-26a] 2 Ti was very inert to the acid 37 and the 1 H NMR signals of (S)-naproxen underwent almost no change even though reaction time was extended to 4 h. On the basis of these facts, it can be concluded that when partially resolved (S)-26a is used, the stable and less reactive heterochiral Schiff base-titanium complex will be formed preferentially in the catalytic system. As a result, the remaining homochiral Schiff base-titanium complex [(S)-26a] 2 Ti with higher ee than that of starting ligand will react with carboxylic acid additive to form the active species which predominates the catalytic process (Scheme 14). The higher reactivity of homochiral titanium complex than its heterochiral counterpart with carboxylic acid can be considered as the origin of positive nonlinear effect ððþÞ-NLE) in the present catalytic system.…”

“…The first synthesis of racemic NOBIN (±)-3 was achieved by Kocovsky in 1991 by the oxidative cross-coupling of a 1:1 mixture of b-naphthylamine and b-naphthol in methanol with a CuCl 2 amine complex as the oxidant [2,4]. The cross-coupling was very selective under optimized conditions, NOBIN (3) could be isolated in up to 85% yield.…”

“…2-Amino-2¢-hydroxy-1,1¢-binaphthyl (NOBIN, 3) could be considered as the hybrid analogue of 1,l¢-bi-2-naphthol (BINOL, 1) and 1,l¢-bi-2-naphthylamine (BINAM, 2) in terms of its functionality and scaffold. Since the first report on the synthesis of NOBIN by Kocovsky [2], it has been recognized as one type of important molecule with increasing application in the construction of chiral ligands for asymmetric catalysis [3]. This review will describe our recent work on the NOBIN chemistry, including the strategies for its synthesis, the development of various chiral ligands using enantiopure NOBIN as the scaffold and their applications in asymmetric catalysis.…”

Novel Chiral 1,3‐Diamines by a Highly Modular Umpolung Strategy Employing a Diastereoselective Fluorination–Nucleophilic Aromatic Substitution Sequence

“…(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) cyclohexane (dach), [2] diphenylethylenediamine (dpen) [3] or diaminobis(naphthalene) (binam). [4] A search using SciFinder, on the other hand, gives just 3 hits when inquiring for "chiral 1,3-diamines": a ferrocene derivative, [5] a class of anilines [6] useful as a chiral proton source, and some diaminopropanes derived from chiral aziridines. [7] Chiral diamines have gained considerable importance in pharmaceutical chemistry, mostly 1,2-diamines, as in the synthesis of tamiflu; [8a,8b] in addition, examples of 1,3-diamines of pharmaceutical importance are known.…”