Synthesis of axially chiral gold complexes and their applications in asymmetric catalyses

Several novel chiral N-heterocyclic carbene and phosphine ligands were prepared from (S)-BINOL. Moreover, their ligated Au complexes were also successfully synthesized and characterized by X-ray crystal diffraction. A weak gold-π interaction between the Au atom and the aromatic ring in these gold complexes was identified. Furthermore, we confirmed the formation of a pair of diastereomeric isomers in NHC gold complexes bearing an axially chiral binaphthyl moiety derived from the hindered rotation around C–C and C–N bonds. In the asymmetric intramolecular hydroamination reaction most of these chiral Au(I) complexes showed good catalytic activities towards olefins tethered with a NHTs functional group to give the corresponding product in moderate yields and up to 29% ee.

The mixture was washed with 1.0 N HCl, followed by water and saturated NaHCO 3 . The organic layer was separated and dried over anhydrous sodium sulfate. The solvent was evaporated and dried under vacuum to yield the solid triflate 7 (1.83 g, 99% yield). This is a known compound. 1

Synthesis of (S)-2'-(3,5-bis(trifluoromethyl)phenyl)-[1,1'-binaphthalen]-2-amine (9)
A solution of 2-benzylamino-1,1'-binaphthyl derivative (S)-8 (856 mg, 1.5 mmol) was dissolved in MeOH (12 mL) in an oven-dried two-neck flask equipped with a argon supply. Under argon, 5% Pd/C (86 mg) was added. The argon atmosphere was then removed under vacuum, and the apparatus was placed under 1 atm of H 2 (hydrogen balloon). The mixture was stirred for overnight under reflux, until complete consumption of starting material was indicated by TLC. The hydrogen atmosphere was then removed under vacuum, and the reaction mixture was flushed generously with nitrogen. The suspended Pd/C was removed by filtration through celite, and the solvent was evaporated to obtain the solid product (S)-9 (685 mg, 95% yield). They are indefinitely stable if stored in an argon atmosphere. This is a known compound. 1

Synthesis of compound (S)-13
The compound (S)-12 (291 mg, 0.5 mmol) and CH 3 I (0.1 mL, 2.0 mmol) in CH 3 CN (2.0 mL) were stirred under reflux for 5 h. After cooling to room temperature, volatiles were removed under reduced pressure and the obtained solid compound (S)-13 (362 mg, quantitative yield) was used for the next reaction without further purification.

Synthesis of compound (S)-14
The compound (S)-12 (291 mg, 0.5 mmol) and BnBr (0.1 mL, 1.0 mmol) in dioxane (2.0 mL) were stirred under reflux for 5 h. After cooling to room temperature, volatiles were removed under reduced pressure and the obtained solid compound (S)-14 (376 mg, quantitative yield) was used for the next reaction without further purification.

Synthesis of gold complex (S)-16
The compound (