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Irreversible Catalytic Ester Hydrolysis of Allyl Esters to Give Acids and Aldehydes by Homogeneous Ruthenium and Ruthenium/Palladium Dual Catalyst Systems
Author(s) -
Nakamura Asami,
Hamasaki Akiyuki,
Goto Sachihiko,
Utsunomiya Masaru,
Tokunaga Makoto
Publication year - 2011
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201000369
Subject(s) - chemistry , ruthenium , phosphine , catalysis , palladium , isomerization , denticity , decarbonylation , hydrolysis , homogeneous catalysis , medicinal chemistry , acetonitrile , organic chemistry , metal
An irreversible hydrolysis reaction of allyl esters ( 1 ) into carboxylic acids ( 2 ) and propanal ( 3 ) was achieved with a ruthenium/palladium (Ru/Pd) dual catalyst system. The optimized catalysts consists of a 1:1:1 mixture of (cyclopentadienyl)tris(acetonitrile)ruthenium hexafluorophosphate {[RuCp(MeCN) 3 ] PF 6 }, bis(acetonitrile)palladium dichloride [PdCl 2 (MeCN) 2 ] and 1,6‐bis(diphenylphosphanyl)hexane (DPPHex). The reaction proceeds via isomerization of allyl esters to 1‐propenyl esters and hydrolysis of them to give 2 and 3 . The first isomerization step was virtually catalyzed by the Ru components and the second hydrolysis step was mainly catalyzed by the Pd components. The optimized bidentate phosphine (DPPHex) which has long alkylene chain effectively generates two vacant sites on the Ru centers by bridging coordination. When a chelating bidentate phosphine such as DPPE was employed, only one vacant site remained on the Ru center and resulted in a low activity. This chelating Ru complex of DPPE formed even in the presence of 2 equivalents of Ru or additional 1 equivalent of Pd. These differences in coordination behaviour between DPPHex and 1,2‐bis(diphenylphosphanyl)ethane (DPPE) cause the differences of the catalytic activity in the first step. The phosphine coordination to Pd center slightly decreases the activity of second hydrolysis step but which was compensated by the increasing of the stability of Pd. On the whole, the optimized Ru/Pd dual catalyst system exhibited good performances on the irreversible hydrolysis of allyl esters.