TY - JOUR
T1 - Ketone H-2-hydrogenation catalysts: Ruthenium complexes with the headphone-like ligand bis(phosphaadamantyl)propane
AU - Hadzovic, A
AU - Lough, A J
AU - Morris, R H
AU - Pringle, P G
AU - Zambrano-Williams, D E
PY - 2006/6/1
Y1 - 2006/6/1
N2 - Treatment of 1,3-diphosphinopropane with acetylacetone in the presence of HCl gives the new chiral bis(phosphaadamantyl)propane ligand (bpap) (1) as a mixture of diastereoisomers. Recrystallization from ethanol gives a mixture enriched in rac diastereoisomer (90% rac/10% meso). The enriched mixture reacts with [RuHCl(PPh3)(3)] in refluxing THF to give [RuHCl(bpap)(PPh3)] (2) in 73% yield. Compound 2 reacts readily with chiral diamines giving octahedral trans-[RuHCl(bpap)(diamine)] complexes 3 (diamine = (1R,2R)-1,2-diaminocyclohexane) and 4 (diamine = (1R,2R)-1,2-diphenylethylenediamine). Compounds 3 and 4 are very active catalysts for H-2-hydrogenation of neat acetophenone in the presence of (KOBu)-Bu-t as a strong base under mild conditions (room temperature, 3 atm of H-2). The low ee values for 1-phenethanol can be attributed to the similar shapes of two terminal adamantoid cages and the flexible backbone of the bpap ligand. The structures of complexes 2 and 3 have been determined by single-crystal X-ray diffraction. (c) 2005 Elsevier B.V. All rights reserved.
AB - Treatment of 1,3-diphosphinopropane with acetylacetone in the presence of HCl gives the new chiral bis(phosphaadamantyl)propane ligand (bpap) (1) as a mixture of diastereoisomers. Recrystallization from ethanol gives a mixture enriched in rac diastereoisomer (90% rac/10% meso). The enriched mixture reacts with [RuHCl(PPh3)(3)] in refluxing THF to give [RuHCl(bpap)(PPh3)] (2) in 73% yield. Compound 2 reacts readily with chiral diamines giving octahedral trans-[RuHCl(bpap)(diamine)] complexes 3 (diamine = (1R,2R)-1,2-diaminocyclohexane) and 4 (diamine = (1R,2R)-1,2-diphenylethylenediamine). Compounds 3 and 4 are very active catalysts for H-2-hydrogenation of neat acetophenone in the presence of (KOBu)-Bu-t as a strong base under mild conditions (room temperature, 3 atm of H-2). The low ee values for 1-phenethanol can be attributed to the similar shapes of two terminal adamantoid cages and the flexible backbone of the bpap ligand. The structures of complexes 2 and 3 have been determined by single-crystal X-ray diffraction. (c) 2005 Elsevier B.V. All rights reserved.
U2 - 10.1016/j.ica.2005.11.018
DO - 10.1016/j.ica.2005.11.018
M3 - Article (Academic Journal)
SN - 0020-1693
VL - 359
SP - 2864
EP - 2869
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
IS - 9
ER -