Synthesis of a novel photoresponsive axially chiral phosphine ligand containing an arylazo group and its application to palladium‐catalyzed asymmetric allylic alkylation

Abstract

Novel photoresponsive axially chiral monophosphine ligands containing azobenzene moiety were prepared and applied to a palladium-catalyzed allylic alkylation. The reaction of rac-1,3-diphenyl-2-propenyl acetate gave the alkylated products with up to 90% enantiomeric excess. The ligand exhibited a trans to cis photoisomerization upon irradiation with UV light.

Supramolecular catalysis. Part 2: artificial enzyme mimics

“…These allosteric catalysts constitute encouraging attempts towards the development of catalysts for which the activity and selectivity can be controlled reversibly along the course of the catalytic reaction. In the examples mentioned above, noncovalent interactions play an important role in the control of the process 666 and the strategy is complementary to the switchable catalysts developed so far in which the activity is controlled by 45 acid/base addition, [667][668][669] by modifying the temperature, [670][671][672][673] the magnetic force, 674,675 the wavelength, 109,147,312,[676][677][678][679][680][681][682][683] the redox potential [684][685][686][687][688] and other parameters. 689 Feringa and co-workers recently reported a system in which both the activity and enantioselectivity of an organocatalytic reaction is tuned by the 50 motion of a molecular motor.…”

Light Switches the Ligand! Photochromic Azobenzene–Phosphanes

“…Early examples of azo-containing phosphanes appeared in 1996, [11][12][13][14][15][17][18][19] but only two examples of catalytic applications are known, and their photochromic properties have never been investigated in depth. [9,10] …”

Dynamic induction of enantiomeric excess from a prochiral azobenzene dimer under circularly polarized light

“…Although 5 has been reported as a byproduct from the action of hydrazines on β-naphthol in the presence of bisulphite, 34 its efficient synthesis and characterization have not been discussed previously. We introduced the azo units through a simple base-catalyzed procedure, reacting 5 with nitrosobenzene in the presence of t -BuOK in t -BuOH/DMSO; 35 we isolated a significant amount of the diazo compound 3 . The 1 H NMR spectrum of 3 features the ortho protons of the azobenzene groups located upfield, appearing as a multiplet along with the naphthyl protons ( δ 7.27–7.46); the other features of the 1 H NMR spectrum matched were as predicted, with the structure supported by 13 C NMR and mass spectral analyses (Fig.…”