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Synthetic Scope of Ru(OH) x /Al 2 O 3 ‐Catalyzed Hydrogen‐Transfer Reactions: An Application to Reduction of Allylic Alcohols by a Sequential Process of Isomerization/Meerwein–Ponndorf–Verley‐Type Reduction
Author(s) -
Kim Jung Won,
Koike Takeshi,
Kotani Miyuki,
Yamaguchi Kazuya,
Mizuno Noritaka
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701917
Subject(s) - allylic rearrangement , catalysis , chemistry , isomerization , enol , ruthenium , medicinal chemistry , alcohol , double bond , transfer hydrogenation , organic chemistry
Reduction of allylic alcohols can be promoted efficiently by the supported ruthenium catalyst Ru(OH) x /Al 2 O 3 . Various allylic alcohols were converted to saturated alcohols in excellent yields by using 2‐propanol without any additives. This Ru(OH) x /Al 2 O 3 ‐catalyzed reduction of a dienol proceeds only at the allylic double bond to afford the corresponding enol, and chemoselective isomerization and reduction can be realized under similar conditions. The catalysis is truly heterogeneous and the high catalytic performance can be maintained during at least three recycles of the Ru(OH) x /Al 2 O 3 catalyst. The transformation of allylic alcohols to saturated alcohols consists of three sequential reactions: oxidation of allylic alcohols to α,β‐unsaturated carbonyl compounds; reduction of α,β‐unsaturated carbonyl compounds to saturated carbonyl compounds; and reduction of saturated carbonyl compounds to saturated alcohols.