{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T10:00:20Z","timestamp":1790935220601,"version":"4.1.0"},"reference-count":84,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2004,1,15]],"date-time":"2004-01-15T00:00:00Z","timestamp":1074124800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chemistry A European J"],"published-print":{"date-parts":[[2004,1,23]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Treatment of complex <jats:italic>trans<\/jats:italic>\u2010[RuCl<jats:sub>2<\/jats:sub>(\u03b7<jats:sup>2<\/jats:sup>\u2010C<jats:sub>2<\/jats:sub>H<jats:sub>4<\/jats:sub>){\u03ba<jats:sup>3<\/jats:sup>\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010(<jats:italic>R<\/jats:italic>,<jats:italic>R<\/jats:italic>)\u2010Ph\u2010pybox}] [(<jats:italic>R<\/jats:italic>,<jats:italic>R<\/jats:italic>)\u2010Ph\u2010pybox = 2,6\u2010bis{4\u2032\u2010(<jats:italic>R<\/jats:italic>)\u2010phenyloxazolin\u20102\u2032\u2010yl}pyridine] with phosphines or phosphites in dichloromethane at 50\u2009\u00b0C leads to the formation of novel ruthenium(<jats:sc>II<\/jats:sc>)\u2010pybox complexes <jats:italic>trans<\/jats:italic>\u2010[RuCl<jats:sub>2<\/jats:sub>(L){\u03ba<jats:sup>3<\/jats:sup>\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010(<jats:italic>R<\/jats:italic>,<jats:italic>R<\/jats:italic>)\u2010Ph\u2010pybox}] [L = PPh<jats:sub>3<\/jats:sub> (<jats:bold>1\u2009a<\/jats:bold>), PPh<jats:sub>2<\/jats:sub>Me (<jats:bold>2\u2009a<\/jats:bold>), PPh<jats:sub>2<\/jats:sub>(C<jats:sub>3<\/jats:sub>H<jats:sub>5<\/jats:sub>) (<jats:bold>3\u2009a<\/jats:bold>), PPh<jats:sub>2<\/jats:sub>(C<jats:sub>4<\/jats:sub>H<jats:sub>7<\/jats:sub>) (<jats:bold>4\u2009a<\/jats:bold>), PMe<jats:sub>3<\/jats:sub> (<jats:bold>5\u2009a<\/jats:bold>), P<jats:italic>i<\/jats:italic>Pr<jats:sub>3<\/jats:sub> (<jats:bold>6\u2009a<\/jats:bold>), P(OMe)<jats:sub>3<\/jats:sub> (<jats:bold>7\u2009a<\/jats:bold>) and P(OPh)<jats:sub>3<\/jats:sub> (<jats:bold>8\u2009a<\/jats:bold>)]. Likewise, reaction of <jats:italic>trans<\/jats:italic>\u2010[RuCl<jats:sub>2<\/jats:sub>(\u03b7<jats:sup>2<\/jats:sup>\u2010C<jats:sub>2<\/jats:sub>H<jats:sub>4<\/jats:sub>){\u03ba<jats:sup>3<\/jats:sup>\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010(<jats:italic>R<\/jats:italic>,<jats:italic>R<\/jats:italic>)\u2010Ph\u2010pybox}] with PPh<jats:sub>3<\/jats:sub> or P<jats:italic>i<\/jats:italic>Pr<jats:sub>3<\/jats:sub> in refluxing methanol leads to the complexes <jats:italic>cis<\/jats:italic>\u2010[RuCl<jats:sub>2<\/jats:sub>(L)(\u03ba<jats:sup>3<\/jats:sup>\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010(<jats:italic>R<\/jats:italic>,<jats:italic>R<\/jats:italic>)\u2010Ph\u2010pybox] [L = PPh<jats:sub>3<\/jats:sub> (<jats:bold>1\u2009b<\/jats:bold>), P<jats:italic>i<\/jats:italic>Pr<jats:sub>3<\/jats:sub> (<jats:bold>6\u2009b<\/jats:bold>)]. No <jats:italic>trans\u2013cis<\/jats:italic> isomerisation of complexes <jats:bold>1\u2009a<\/jats:bold>\u2013<jats:bold>8\u2009a<\/jats:bold> has been observed. Complexes <jats:bold>1\u2009a<\/jats:bold>\u2013<jats:bold>8\u2009a<\/jats:bold>, <jats:bold>1\u2009b<\/jats:bold>, <jats:bold>6\u2009b<\/jats:bold> together with the analogous <jats:italic>trans<\/jats:italic>\u2010[RuCl<jats:sub>2<\/jats:sub>{P(OMe)<jats:sub>3<\/jats:sub>}{\u03ba<jats:sup>3<\/jats:sup>\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010(<jats:italic>S<\/jats:italic>,<jats:italic>S<\/jats:italic>)\u2010<jats:italic>i<\/jats:italic>Pr\u2010pybox}] (<jats:bold>10\u2009a<\/jats:bold>) and the previously reported <jats:italic>trans<\/jats:italic>\u2010 and <jats:italic>cis<\/jats:italic>\u2010[RuCl<jats:sub>2<\/jats:sub>(PPh<jats:sub>3<\/jats:sub>){\u03ba<jats:sup>3<\/jats:sup>\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010(<jats:italic>S<\/jats:italic>,<jats:italic>S<\/jats:italic>)\u2010<jats:italic>i<\/jats:italic>Pr\u2010pybox}] (<jats:bold>9\u2009a<\/jats:bold> and <jats:bold>9\u2009b<\/jats:bold>, respectively) are active catalysts for the transfer hydrogenation of acetophenone in 2\u2010propanol in the presence of NaOH (ketone\/cat\/NaOH 500:1:6). <jats:italic>cis<\/jats:italic>\u2010Ph\u2010pybox derivatives are the most active catalysts. In particular, <jats:italic>cis<\/jats:italic> complexes <jats:bold>1\u2009b<\/jats:bold> and <jats:bold>6\u2009b<\/jats:bold> led to almost quantitative conversions in less than 5 min with a high enantioselectivity (up to 95\u2009%). A variety of aromatic ketones have also been reduced to the corresponding secondary alcohols with very high TOF and <jats:italic>ee<\/jats:italic> up to 94\u2009%. The overall catalytic performance seems to be a subtle combination of the steric and\/or electronic properties both the phosphines and the ketones. A high TOF (27\u2009300 h<jats:sup>\u22121<\/jats:sup>) and excellent <jats:italic>ee<\/jats:italic> (94\u2009%) have been found for the reduction of 3\u2010bromoacetophenone with catalyst <jats:bold>6\u2009b<\/jats:bold>. Reductions of alkyl ketones also proceed with high and rapid conversions but low enantioselectivities are achieved.<\/jats:p>","DOI":"10.1002\/chem.200305170","type":"journal-article","created":{"date-parts":[[2004,1,16]],"date-time":"2004-01-16T10:48:58Z","timestamp":1074250138000},"page":"425-432","source":"Crossref","is-referenced-by-count":91,"title":["New Chiral Ruthenium(<scp>II<\/scp>) Catalysts Containing 2,6\u2010Bis(4\u2032\u2010(<i>R<\/i>)\u2010phenyloxazolin\u20102\u2032\u2010yl)pyridine (Ph\u2010pybox) Ligands for Highly Enantioselective Transfer Hydrogenation of Ketones"],"prefix":"10.1002","volume":"10","author":[{"given":"Dar\u00edo","family":"Cuervo","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. 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Res."},{"key":"e_1_2_7_37_3","author":"on special issue","journal-title":"Catalytic Asymmetric Synthesis."},{"key":"e_1_2_7_38_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0957-4166(98)00093-7"},{"key":"e_1_2_7_39_2","unstructured":"\u00a0"},{"key":"e_1_2_7_40_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja974095p"},{"key":"e_1_2_7_41_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-328X(02)01767-9"},{"key":"e_1_2_7_42_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(01)89371-6"},{"key":"e_1_2_7_43_2","unstructured":"\u00a0"},{"key":"e_1_2_7_44_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4039(97)00360-2"},{"key":"e_1_2_7_45_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0957-4166(97)00396-0"},{"key":"e_1_2_7_46_2","unstructured":"A series of ruthenium complexes containing tridentate N P N ligands have also been found to be active in asymmetric transfer hydrogenation:"},{"key":"e_1_2_7_47_2","doi-asserted-by":"publisher","DOI":"10.1016\/0040-4039(95)02298-8"},{"key":"e_1_2_7_48_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4039(96)02257-5"},{"key":"e_1_2_7_49_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4039(97)01496-2"},{"key":"e_1_2_7_50_2","unstructured":"For a review see ref. [4d]; for recent catalytic applications of pybox complexes see:"},{"key":"e_1_2_7_51_2","doi-asserted-by":"publisher","DOI":"10.1021\/ma981957d"},{"key":"e_1_2_7_52_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja9829822"},{"key":"e_1_2_7_53_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja982983u"},{"key":"e_1_2_7_54_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja991191c"},{"key":"e_1_2_7_55_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol005721h"},{"key":"e_1_2_7_56_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja015612d"},{"key":"e_1_2_7_57_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja011983i"},{"key":"e_1_2_7_58_2","doi-asserted-by":"publisher","DOI":"10.1039\/b008516m"},{"key":"e_1_2_7_59_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol015859f"},{"key":"e_1_2_7_60_2","doi-asserted-by":"publisher","DOI":"10.1039\/B207093F"},{"key":"e_1_2_7_61_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja026007t"},{"key":"e_1_2_7_62_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja028676c"},{"key":"e_1_2_7_63_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(01)01129-2"},{"key":"e_1_2_7_64_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(02)00978-X"},{"key":"e_1_2_7_65_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0957-4166(03)00168-X"},{"key":"e_1_2_7_66_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic9813258"},{"key":"e_1_2_7_67_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00084a104"},{"key":"e_1_2_7_68_2","unstructured":"See for instance:"},{"key":"e_1_2_7_69_2","doi-asserted-by":"publisher","DOI":"10.1246\/bcsj.68.1247"},{"key":"e_1_2_7_70_2","unstructured":"according to ref. [14k]: copper(I)\u2010Ph\u2010pybox complexes are more active and enantioselective catalysts in the addition of terminal alkynes to imines than the correspondingiPr\u2010pybox analogues."},{"key":"e_1_2_7_71_2","unstructured":"Complex10\u2009ahas been prepared by heating a mixture of [RuCl2(\u03b72\u2010C2H4){\u03ba3\u2010N N N\u2010(S S)\u2010iPr\u2010pybox}] and an excess of P(OMe)3at 40\u2009\u00b0C in dichloromethane for 1 h (35\u2009% yield) (unpublished results from this laboratory)."},{"key":"e_1_2_7_72_2","unstructured":"For complexes containing the allyl\u2010substituted phosphines an improvement in performance has been obtained by adding the base 10 min before the ketone (entry 3 vs 2). This fact may be explained by assuming an isomerisation of the allyl group in the presence of base which may occur before the chloride abstraction from the metal. Therefore the active species probably contain diphenyl(2\u2010methylvinyl)phosphine."},{"key":"e_1_2_7_73_2","unstructured":"Pathways that favour the reverse reaction leading to loss ofeecannot be discarded either."},{"key":"e_1_2_7_74_2","unstructured":"We have found that a base\/catalyst of ca. 24:1 leads to better conversions for these substrates in contrast to the ratio (ca. 6:1) found for acetophenone."},{"key":"e_1_2_7_75_2","unstructured":"For a short review and mechanistic studies see:"},{"key":"e_1_2_7_76_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-328X(02)01316-5"},{"key":"e_1_2_7_77_2","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3765(20011203)7:23<5052::AID-CHEM5052>3.0.CO;2-Z"},{"key":"e_1_2_7_78_2","unstructured":"The dissociation of the coordinated phosphine or phosphite has to be discarded; otherwise no influence oneevalues would be observed."},{"key":"e_1_2_7_79_2","doi-asserted-by":"publisher","DOI":"10.1021\/om990210o"},{"key":"e_1_2_7_80_2","unstructured":"From Aldrich 2003\u20132004: (R R)\u2010Ph\u2010pybox (49\u2009606\u20105); (S S)\u2010Ph\u2010pybox (49\u2009607\u20103). From TCI 2003: (R R)\u2010Ph\u2010pybox (B2219); (S S)\u2010Ph\u2010pybox (B2220)."}],"container-title":["Chemistry \u2013 A European Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fchem.200305170","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/chem.200305170","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T20:30:55Z","timestamp":1760301055000},"score":1,"resource":{"primary":{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/10.1002\/chem.200305170"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,1,15]]},"references-count":84,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2004,1,23]]}},"alternative-id":["10.1002\/chem.200305170"],"URL":"https:\/\/doi.org\/10.1002\/chem.200305170","archive":["Portico"],"relation":{},"ISSN":["0947-6539","1521-3765"],"issn-type":[{"value":"0947-6539","type":"print"},{"value":"1521-3765","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,1,15]]}}}