Copper-Catalyzed Synthesis of Axially Chiral Biaryls with Diaryliodonium Salts as Arylation Reagents

Abstract

NOBIN and BINAM derivatives harboring biaryl frameworks are recognized as a class of important atropisomers with versatile applications. Here, we present an efficient synthetic route to access such compounds through copper-catalyzed domino arylation of N-arylhydroxylamines or N-arylhydrazines with diaryliodonium salts and [3,3]-sigmatropic rearrangement. This reaction features mild conditions, good substrate compatibility, and excellent efficiency. The practicality of this protocol was further extended by the synthesis of biaryl amino alcohols.

Selective N-functionalization of Arylhydrazines with Primary Alcohols and Acids under PPh3/DDQ System

“…29 Brown liquid (51.3 mg, 75% yield); R f = 0.4 (5:1 PE/EA); 1 H NMR (400 MHz, CDCl 3 ) δ 7.36−7.25 (m, 5H), 7.07 (d, J = 9.0 Hz, 2H), 6.84 (d, J = 9.0 Hz, 2H), 4.43 (s, 2H), 3.77 (s, 3H), 3.25 (brs, 2H); 13 1-Benzyl-1-(naphthalen-2-yl)hydrazine (3ga). 30 Brown solid (52.8 mg, 71% yield); mp 67−69 °C; R f = 0.5 (5:1 PE/EA); 1 H NMR (400 MHz, CDCl 3 ) δ 7.73−7.68 (m, 2H), 7.65 (d, J = 8.2 Hz, 1H), 7.45 (dd, J = 9.0, 2.4 Hz, 1H), 7.37 (t, J = 7.5 Hz, 1H), 7.33−7.21 (m, 7H), 4.65 (s, 2H), 3.59 (brs, 2H); 13 1-Benzyl-1-(4-fluorophenyl)hydrazine (3ha). 25 Yellow liquid (60.9 mg, 94% yield); R f = 0.7 (5:1 PE/EA); 1 H NMR (400 MHz, CDCl 3 ) δ 7.37−7.24 (m, 5H), 7.05 (dd, J = 9.1, 4.6 Hz, 2H), 6.94 (t, J = 8.7 Hz, 2H), 4.50 (s, 2H), 3.47 (brs, 2H); 13 1-Benzyl-1-(4-chlorophenyl)hydrazine (3ia).…”

Recent Progress in Cyclic Aryliodonium Chemistry: Syntheses and Applications

“…In the past decade, a number of synthetic transformations and applications utilizing cyclic aryliodoniums have been reported. ,,− The domino arylation procedures are utilized to access more complicated polycycles through the construction of C–C and C–heteroatom bonds. In the past five years, significant advancements have been also made in enantioselective ring-opening reactions of cyclic aryliodoniums with nucleophiles to construct axially chiral atropisomers, which represent an important motif in natural products, − biologically active compounds, − and chiral ligands. − Based on the currently available literature, we summarize a recent progress on the use of cyclic aryl iodoniums as electrophilic aryl transfer reagents for the bond formations of C–N, C–O, C–C, and C–other atom (including S, Se, Si, Te) to construct polycyclic compounds and facilitate the synthesis of axially chiral atropisomers. The synthetically appealing protocols for the arylation of various nucleophiles with cyclic aryliodoniums have been well developed.…”

Diaryliodonium(iii) salts in one-pot double functionalization of C–IIIIandorthoC–H bonds

“…O -Arylation of N -hydroxyaniline ( 24 and 27 ) proceeds with diaryliodonium salt to generate N , O -diarylhydroxylamine, which undergoes [3,3]-rearrangement to afford a highly functionalized biphenyl with both hydroxy and amino groups on each phenyl ring ( 25 and 28 ) (Scheme 11). 42,43 This transformation can be applied to the transition-metal-free synthesis of 2-amino-2′-hydroxy-1,1′-binaphthyl (NOBIN)-type ligands as described below.…”