Ketone H-2-hydrogenation catalysts: Ruthenium complexes with the headphone-like ligand bis(phosphaadamantyl)propane

A Hadzovic, A J Lough, R H Morris, P G Pringle, D E Zambrano-Williams

Research output: Contribution to journalArticle (Academic Journal)peer-review

18 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)2864-2869
Number of pages6
JournalInorganica Chimica Acta
Volume359
Issue number9
DOIs
Publication statusPublished - 1 Jun 2006

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