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Cobalt-catalysed alkene hydrogenation: a metallacycle can explain the hydroxyl activating effect and the diastereoselectivity

Cobalt-catalysed alkene hydrogenation: a metallacycle can explain the hydroxyl activating effect... Recently, Chirik and co-workers reported bis(phosphine)cobalt dialkyl complexes for the hydrogenation of alkenes under mild conditions (). A significant activating effect by hydroxyl groups was observed for the cobalt catalysts. Ether, ester, or ketone groups did not provide such an effect. The reported cobalt dialkyl catalyst dppeCo(CH2SiMe3)2 (, dppe = 1,2-bis(diphenylphosphino)ethane) catalyses hydrogenation of terpinen-4-ol providing 99% conversion (entry 2, ), whereas the corresponding methyl ether displays <5% conversion despite higher catalyst loading and longer reaction time (entry 3, ). Interestingly, hydrogenation of terpinen-4-ol gives a high diastereoselectivity with a diastereomeric ratio (d.r.) of 99.8 : 0.2 (entry 2, ). Compared to tri-substituted alkenes, di-substituted terminal alkenes could be hydrogenated without a hydroxyl group present (entry 4, ). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Chemical Science Royal Society of Chemistry

Cobalt-catalysed alkene hydrogenation: a metallacycle can explain the hydroxyl activating effect and the diastereoselectivity

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References (29)

Publisher
Royal Society of Chemistry
Copyright
This journal is © The Royal Society of Chemistry
ISSN
2041-6520
eISSN
2041-6539
DOI
10.1039/c8sc01315b
Publisher site
See Article on Publisher Site

Abstract

Recently, Chirik and co-workers reported bis(phosphine)cobalt dialkyl complexes for the hydrogenation of alkenes under mild conditions (). A significant activating effect by hydroxyl groups was observed for the cobalt catalysts. Ether, ester, or ketone groups did not provide such an effect. The reported cobalt dialkyl catalyst dppeCo(CH2SiMe3)2 (, dppe = 1,2-bis(diphenylphosphino)ethane) catalyses hydrogenation of terpinen-4-ol providing 99% conversion (entry 2, ), whereas the corresponding methyl ether displays <5% conversion despite higher catalyst loading and longer reaction time (entry 3, ). Interestingly, hydrogenation of terpinen-4-ol gives a high diastereoselectivity with a diastereomeric ratio (d.r.) of 99.8 : 0.2 (entry 2, ). Compared to tri-substituted alkenes, di-substituted terminal alkenes could be hydrogenated without a hydroxyl group present (entry 4, ).

Journal

Chemical ScienceRoyal Society of Chemistry

Published: Jun 6, 2018

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