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Article: Enantioselective intramolecular cyclopropanation of cis-alkenes by chiral ruthenium (II) Schiff base catalysts and crystal structures of (Schiff base) ruthenium complexes containing carbene, PPh 3, and CO ligands

TitleEnantioselective intramolecular cyclopropanation of cis-alkenes by chiral ruthenium (II) Schiff base catalysts and crystal structures of (Schiff base) ruthenium complexes containing carbene, PPh 3, and CO ligands
Authors
Issue Date2006
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/organometallics
Citation
Organometallics, 2006, v. 25 n. 7, p. 1676-1688 How to Cite?
AbstractThe enantioselective intramolecular cyclopropanation of cis-substituted allylic diazoacetates catalyzed by the chiral ruthenium Schiff base complexes [Ru(Schiff base)(PPh3)2] (1) is described. Among this class of complexes examined, [Ru(2-Br-salen)(PPh 3) 2] (la) is the most effective, catalyzing intramolecular cyclopropanation of c/s-allylic diazoacetates cis-(CRH=CH)CH 2OC(O)CHN 2 (R - alkyl, aryl) in CHCI 3 solution to give [3.1.0]-bicyclic lactones with yields and ee values up to 71 and 90%, respectively. The analogous reactions of c/s-alkenyl diazoacetates using [Ru(Schiff base)(CO)] (2) as catalyst gave comparable enantioselectivities (up to 91% ee) but lower product yields of 20-38%. Treatment of [Ru-(2,4-X-salen)(PPh 3) 2] (1d, X = Br; 1e, X = Cl; 1f, X = I) with N 2C(p-YC 6H 4) 2 (Y = H, MeO) and N-methylimidazole (MeIm) or pyridine (py) gave the monocarbene complexes [Ru(2,4-X-salen)(C(p-YC 6H 4) 2)(MeIm)] (3a, X = Br, Y = H; 3b, X = Cl, Y = H; 3c, X = I, Y = H; 3d, X = Br, Y = OMe) and [Ru(2,4-Br-salen)(CPh 2)(py)] (4, H 2(2,4-Br-salen) = bis(3,5-dibromosalicylidene)-(1R,2R)-cyclo-hexanediamine), respectively. X-ray crystal structure determinations revealed Ru=C(carbene) distances of 1.921(12) Å for 3a, 1.913(5) Å for 3b, 1.919(14) Å for 3c, 1.910(2) Å for 3d, and 1.917(4) Å for 4. A comparison of the structures and electrochemistry of 1, [Ru(Schiff base)(CO)(MeIm)], 3, and 4 with those of the porphyrin analogues is presented. © 2006 American Chemical Society.
Persistent Identifierhttp://hdl.handle.net/10722/168011
ISSN
2015 Impact Factor: 4.186
2015 SCImago Journal Rankings: 2.043
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLi, GYen_HK
dc.contributor.authorZhang, Jen_HK
dc.contributor.authorChan, PWHen_HK
dc.contributor.authorXu, ZJen_HK
dc.contributor.authorZhu, Nen_HK
dc.contributor.authorChe, CMen_HK
dc.date.accessioned2012-10-08T03:14:05Z-
dc.date.available2012-10-08T03:14:05Z-
dc.date.issued2006en_HK
dc.identifier.citationOrganometallics, 2006, v. 25 n. 7, p. 1676-1688en_HK
dc.identifier.issn0276-7333en_HK
dc.identifier.urihttp://hdl.handle.net/10722/168011-
dc.description.abstractThe enantioselective intramolecular cyclopropanation of cis-substituted allylic diazoacetates catalyzed by the chiral ruthenium Schiff base complexes [Ru(Schiff base)(PPh3)2] (1) is described. Among this class of complexes examined, [Ru(2-Br-salen)(PPh 3) 2] (la) is the most effective, catalyzing intramolecular cyclopropanation of c/s-allylic diazoacetates cis-(CRH=CH)CH 2OC(O)CHN 2 (R - alkyl, aryl) in CHCI 3 solution to give [3.1.0]-bicyclic lactones with yields and ee values up to 71 and 90%, respectively. The analogous reactions of c/s-alkenyl diazoacetates using [Ru(Schiff base)(CO)] (2) as catalyst gave comparable enantioselectivities (up to 91% ee) but lower product yields of 20-38%. Treatment of [Ru-(2,4-X-salen)(PPh 3) 2] (1d, X = Br; 1e, X = Cl; 1f, X = I) with N 2C(p-YC 6H 4) 2 (Y = H, MeO) and N-methylimidazole (MeIm) or pyridine (py) gave the monocarbene complexes [Ru(2,4-X-salen)(C(p-YC 6H 4) 2)(MeIm)] (3a, X = Br, Y = H; 3b, X = Cl, Y = H; 3c, X = I, Y = H; 3d, X = Br, Y = OMe) and [Ru(2,4-Br-salen)(CPh 2)(py)] (4, H 2(2,4-Br-salen) = bis(3,5-dibromosalicylidene)-(1R,2R)-cyclo-hexanediamine), respectively. X-ray crystal structure determinations revealed Ru=C(carbene) distances of 1.921(12) Å for 3a, 1.913(5) Å for 3b, 1.919(14) Å for 3c, 1.910(2) Å for 3d, and 1.917(4) Å for 4. A comparison of the structures and electrochemistry of 1, [Ru(Schiff base)(CO)(MeIm)], 3, and 4 with those of the porphyrin analogues is presented. © 2006 American Chemical Society.en_HK
dc.languageengen_US
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/organometallicsen_HK
dc.relation.ispartofOrganometallicsen_HK
dc.titleEnantioselective intramolecular cyclopropanation of cis-alkenes by chiral ruthenium (II) Schiff base catalysts and crystal structures of (Schiff base) ruthenium complexes containing carbene, PPh 3, and CO ligandsen_HK
dc.typeArticleen_HK
dc.identifier.emailZhu, N: nzhu@hkucc.hku.hken_HK
dc.identifier.emailChe, CM: cmche@hku.hken_HK
dc.identifier.authorityZhu, N=rp00845en_HK
dc.identifier.authorityChe, CM=rp00670en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1021/om051009ien_HK
dc.identifier.scopuseid_2-s2.0-33645813799en_HK
dc.identifier.hkuros121170-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33645813799&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume25en_HK
dc.identifier.issue7en_HK
dc.identifier.spage1676en_HK
dc.identifier.epage1688en_HK
dc.identifier.isiWOS:000236288100019-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridLi, GY=15765581300en_HK
dc.identifier.scopusauthoridZhang, J=16148295400en_HK
dc.identifier.scopusauthoridChan, PWH=13607033800en_HK
dc.identifier.scopusauthoridXu, ZJ=8708548900en_HK
dc.identifier.scopusauthoridZhu, N=7201449530en_HK
dc.identifier.scopusauthoridChe, CM=7102442791en_HK

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