Axially Chiral Biaryl Monophosphine Oxides Enabled by Palladium/WJ-Phos-Catalyzed Asymmetric Suzuki–Miyaura Cross-coupling

Abstract

A highly enantioselective palladium/WJ-Phos-catalyzed Suzuki−Miyaura coupling reaction for efficient construction of axially chiral biaryl monophosphine oxides was developed. A series of axially chiral biaryl monophosphine oxides were obtained in good yields and with high enantioselectivities. The practicability of this reaction was validated in the straightforward synthesis of axially chiral biaryl monophosphine ligand and demonstrated by a 100-g-scale synthesis. Moreover, various functionalizations of the product make it as a platform molecule for synthesis of other chiral biaryl phosphines.

Homogeneous Palladium-Catalyzed Selective Reduction of 2,2′-Biphenols Using HCO2H as Hydrogen Source

“…In these cases, good or high yields and enantioselectivities could be achieved without optimization of conditions. 6,16 In summary, we have developed an efficient homogeneous palladium-catalyzed selective deoxygenation of 2,2′biphenols by reduction of aryl triflates with formic acid. This process features high efficiency, broad substrate scope, and easy gram-scale preparation.…”

“…13 C NMR (100 MHz, CDCl 3 ):  = 150.7, 145. 6,138.9,133.1,131.6,131.2,130.8,130.3,130.1,122.3,121.7,118.5 (q,J = 320.4 Hz),116.1,20.9,20.4.…”

“…13 C NMR (101 MHz, CDCl 3 ):  = 152. 6,147.1,142.1,140.5,139.1,134.5,131.6,131.4,130.2,129.24,129.18,128.9,128.6,128.4,127.4,127.1,127.0,122.8,122.6,118.6 (d,J = 320.6 Hz), 116.8.…”

“…13 C NMR (100 MHz, CDCl 3 ):  = 148. 6,148.3,141.9 (d,J = 6.1 Hz),137.8 (d,J = 11.9 Hz), 136.0 (d, J = 14.2 Hz), 134.2, 134.0 (d, J = 19.9 Hz), 130.2 (d, J = 4.8 Hz), 129.9 (d,J = 3.7 Hz),128.8,128.6,128.5 (d,J = 6.8 Hz),127.7 ,127.4 (d,J = 19.0 Hz).…”

“…4 The selective deoxygenation of 2,2′-biphenols has important applications in organic synthesis, especially for the preparation of useful ligands, catalysts, and heterocycles bearing biphenyl skeleton. 5,6 However, there is only one reliable and commonly used method for binaphthol (Scheme 1A). 5k,7 Binaphthol was first converted into monotriflate, and then was reduced by heterogeneous Pd/C-catalyzed hydrogenation with hydrogen gas.…”