Enantioselective Rh-Catalyzed Arylation of N-Tosylarylimines with Arylboronic Acids

Abstract

The asymmetric arylation of N-tosylarylimines with arylboronic acids was realized by using rhodium/(S)-ShiP as catalyst. The reaction proceeded in aqueous toluene to give diarylmethylamines in good yields with up to 96% ee. [reaction: see text]

An N‐Linked Bidentate Phosphoramidite Ligand (N‐Me‐BIPAM) for Rhodium‐Catalyzed Asymmetric Addition of Arylboronic Acids to N‐Sulfonylarylaldimines

“…Arylboronic acid (0.75 mmol) and aldimine (9 or 10, 0.5 mmol) were added to this catalyst solution. After being stirred for 16 h at 50 8C, the product was extracted with ethyl acetate, washed with brine and dried over MgSO 4 . Chromatography on silica gel with hexane/ethyl acetate gave the product as white or yellow solids.…”

“…Thus, the performance of N-Me-BIPAM is comparable to or even higher than that of ligands previously reported for analogous arylations of imines. [3][4][5][6][7][8] However, this ligand may prefer some steric hindrance of substituents since the reaction often resulted in less than 90% ee when an unsubstituted phenyl group was used for either of the two aryl rings (entries 1, 2, 19, 21 28, 30 and 35). This is due to steric reasons rather than an electronic effect of substituents because high selectivities were easily achieved in all combinations of two aryl rings possessing substituents in both rings.…”

“…Among these extensive studies on catalytic addition of metallic and non-metallic compounds to aldimines, the use of arylboronic acids has attracted much attention due to their low toxicity, compatibility to a broad range of functional groups and high stability in water and air. The enantioselective rhodium-catalyzed arylation of aldimines with arylboroxines or arylboronic acids has been studied by Tomioka, [3] Zhou, [4] de Vries, Feringa and Minnerd, [5] Ellman, [6] Hayashi, [7] as well as Xu and Lin. [8] Amidophosphane (1), spiromonophosphite (2), bicycloA C H T U N G T R E N N U N G [2.2.2]octadiene (6), bicycloA C H T U N G T R E N N U N G [3.3.1]nonadiene (7) and tetrahydropentalene (8) were found to be effective as the chiral ligand for arylation of N-tosyl-(4-MeC 6 H 4 SO 2 ) and N-nosylimines (4-NO 2 C 6 H 4 SO 2 ) ( Figure 1).…”

N-(Alkylsulfamoyl)aldimines: easily deprotected precursors for diarylmethylamine synthesis

“…Initial optimisation concentrated on imines 9a-d as representative examples of electron neutral and moderately electron deficient imines in the presence of the Rh I -L based catalyst (3 mol% based on 9 using L A or L B ). The biphasic conditions of Zhou [16] proved most appropriate for use of boronic acids (Table 1). …”

Enantioselective Synthesis of Arylglycine Derivatives by Asymmetric Addition of Arylboronic Acids to Imines

“…DME (2.0 mL) was added to the flask and the mixture was then stirred at 50 °C for 16 h, at which time the crude reaction mixture extracted using ethyl acetate, washed with saturated NH 4 Cl and brine, and dried over MgSO 4 . Chromatography of the crude reaction mixture on silica gel gave (S)-N-(2-(furanyl)(phenyl)methyl)-4-methylbenzenesulfonamide (5a) [14,16,18,19,30] …”