Asymmetric catalysis of homo‐coupling of 3‐substituted naphthylamine and hetero‐coupling with 3‐substituted naphthol leading to 3,3′‐dimethyl‐2,2′‐diaminobinaphthyl and ‐2‐amino‐2′‐hydroxybinaphthyl

Abstract

Optically active 3,3'-dimethyl-2,2'-diamino-1,1'-binaphthyl (DM-DABN) and 3,3'-dimethyl-2-amino-2'-hydroxybinaphthyl (DM-NOBIN) derivatives were synthesized by Cu-(-)-sparteine complex-catalyzed enantioselective homo- and hetero-coupling of 2-naphthylamine, respectively. The difference in enantioselectivity was observed by changing the concentration of oxygen.

Aerobic Copper-Catalyzed Organic Reactions

“…1062 The desired product was obtained in moderate yield and low selectivity along with significant amounts of byproducts from C-N bond forming pathways (Scheme 502). In the presence of equal amounts of a naphthol substrate, heterocoupling could also be effected, with the dimeric naphthol produced as the major byproduct (Scheme 503).…”

Enantioselective Synthesis of 3,3′‐Disubstituted 2‐Amino‐2′‐hydroxy‐1,1′‐binaphthyls by Copper‐Catalyzed Aerobic Oxidative Cross‐Coupling

“…Therefore, development of an effective and direct catalytic system accessing to the enantioenriched 3,3′‐disubstituted NOBINs via asymmetric oxidative cross‐coupling remains a significant task to be accomplished. Inspired by pioneer's work together with our successful SPD (spirocyclic pyrrolidine) catalysts in asymmetric catalysis, [6f, 12, 13] herein, we present our efforts toward this challenging cross‐coupling of 2‐naphthylamine and 2‐naphthol to synthesize the enantioenriched 3,3′‐disubstituted NOBINs utilizing our novel Cu I /SPDO system (Scheme 1 c).…”

Studies towards the N-acylative kinetic resolution of NOBIN

“…MS (EI + ) m/z (rel. int., %): 299 (100, M •+ ), 284 (10), 267 (27), 254 (11), 239 (10), 226 (6), 156 (14), 143 (4), 134 (12), 127 (6), 120 5 39,45 (0.8 mg, 5 mole %), NOMBIN (2; 0.015 g, 0.05 mmol), 18-crown-6 (0.010 g, 0.0375 mmol), anhydrous LiBr (0.0065 g, 0.075 mmol), and the vial was sealed with an air-tight aluminium/rubber septum using a crimper. The contents in the vial was dried in vacuo and purged with argon gas (3×).…”

“…Kočovský has also shown that partial optical resolution concomitant with oxidative coupling can be achieved by inclusion of a stoichiometric amount of various chiral amines in place of tert-butylamine during oxidative coupling. This allows for initial precipitation of a complex of NOBIN, the copper salt and the chiral amine in up to 46% ee and subsequent fractional crystallisation can yield product with high levels of optical purity [7][8][9][10][11] . Optical resolution of scalemic or (±)-NOBIN by classical crystallisation with camphor sulfonic acid 12,13 , by imine exchange of achiral imine derivatives with chiral amines 14 and by inclusion complexation with N-benzyl cinchonidinium chloride 15 are alternative methods to obtain enantiomerically highly enriched (R)-or (S)-NOBIN.…”