Shintani, Ryo; Duan, Wei-Liang; Hayashi, Tamio published the artcile< Rhodium-Catalyzed Asymmetric Construction of Quaternary Carbon Stereocenters: Ligand-Dependent Regiocontrol in the 1,4-Addition to Substituted Maleimides>, Reference of 139139-86-9, the main research area is rhodium complex asym addition reaction regioselectivity enantioselectivity; arylboronic acid maleimide asym addition reaction.
A rhodium-catalyzed asym. 1,4-addition of arylboronic acids of formula ArB(OH)2 (Ar = Ph, 2-naphthyl, 2-methylphenyl, 4-methoxyphenyl, 4-fluorophenyl) to substituted maleimides (I; R = Et, Me, i-Pr) has been described. The regioselectivity in this reaction is controlled by the choice of ligand (dienes or bisphosphines), and 1,4-adducts with a quaternary stereocenter (II; Ar, R = same as above) can be obtained with high regio- and enantioselectivity over 1,4-adducts with a secondary carbon center (III; Ar, R = same as above) by the use of (R)-H8-BINAP (IV). For example, I (R = Et), 3.0 equiv phenylboronic acid, 2.5 mol% divinylrhodium chloride dimer, IV (Rh/ligand = 1:1), and 0.5 equiv KOH were stirred in a 10:1 mixture of dioxane and water at 50° for 3 h to give a 87:13 mixture of II (Ar = Ph, R = Et) and III (Ar = Ph, R = Et) in 98% yield.
Journal of the American Chemical Society published new progress about Boronic acids Role: RCT (Reactant), RACT (Reactant or Reagent) (arylboronic acids). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Reference of 139139-86-9.
Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate