37737-62-5Relevant articles and documents
Catalyzed hydroboration of nitrostyrenes and 4-vinylaniline: A mild and selective route to aniline derivatives containing boronate esters
Vogels, Christopher M.,Decken, Andreas,Westcott, Stephen A.
, p. 2419 - 2422 (2007/10/03)
Transition metal catalyzed reactions of catecholborane (HBcat; cat = 1,2-O2C6H4) with β-nitrostyrene and 3-nitrostyrene lead to products derived from competing hydrogenation and hydroboration of the alkene unit along with reduction of the nitro group. Hydroboration of 4-vinylaniline gave regioselective formation of either the branched or the linear organoboronate ester depending upon the catalyst precursors (i.e., RhCl(PPh3)3 or Rh(acac)(dppe) vs [Cp*IrCl2]2) used to facilitate this reaction. Hydroboration products were converted to air-stable primary amines by addition of pinacol.
Metal-catalyzed hydroboration and diboration of thiocarbonyls and vinyl sulfides
Carter, Charles A.G.,Vogels, Christopher M.,Harrison, Daniel J.,Karen,Gagnon,Norman, David W.,Langler, Richard F.,Baker, R. Thomas,Westcott, Stephen A.
, p. 2130 - 2132 (2008/10/08)
α-Thioboronate esters are obtained directly in high yield and selectivity from metal-catalyzed additions of B-X bonds (X = H, B) to thiocarbonyl compounds and vinyl sulfides.
Nucleophile promoted degradation of catecbolborane: Consequences for transition metal-catalyzed hydroborations
Westcott, Stephen A.,Blom, Henk P.,Marder, Todd B.,Baker, R. Thomas,Calabrese, Joseph C.
, p. 2175 - 2182 (2008/10/08)
Reactions of tertiary phosphines or phosphinorhodium complexes with catecholborane (HB(cat)) give boron-substituent redistribution products. While sterically compact phosphines (PMe3, PEt3, PMe2Ph) react with 1 equiv of HBcat to give [(PR3)2BH2]+[B(cat) 2]-, bulkier phosphines (PPh3, PPri3, PCy3) afford phosphine-boranes H3B·PR3 and tris(catecholato)diboron, B2(cat)3. Reactions of HB(cat) with coordinatively saturated [RhH(DPPP)2] (DPPP = 1,3-bis(diphenylphosphino)propane) and [RhH(PMe3)4] afforded cationic species [RhH2(DPPP)2]+[B(cat)2]- and [RhH2(PMe3)4]+[B(cat) 2]- respectively, both of which are active catalyst precursors for addition of HB(cat) to 4-vinylanisole. These catalyzed hydroborations, however, gave significant amounts of BH3-derived products, arising from Rh-mediated HB(cat) degradation. The only catalyst precursors examined which did not lead to degradation of HB(cat) were rhodium(I) chloride complexes containing basic monodentate phosphines. Molecular structures of B2(cat)3 (3), [(PEt3)2BH2] [B(cat)2] (4b), and [RhH2(PMe3)4] [B(cat)2] (9) were determined by single crystal X-ray diffraction. Colorless crystals of 3 are monoclinic, P21/c (No. 14), with four molecules per unit cell of dimensions a = 12.922(5) A?, b = 12.245(2) A?, c = 10.784(8) A?, and β= 109.03°. Colorless crystals of 4b are monoclinic, P21/n (No. 14), with eight molecules per unit cell of dimensions a - 17.453(6) A?, b = 11.414(1) A?, c = 26.666(9) A?, and β = 95.17(2)°. Orange crystals of 9 are trigonal, P3221 (No. 154), with three molecules per unit cell of dimensions a = 13.222(1) A?, b = 13.222(1) A?, and c = 17.294(6) A?.
