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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
Title | 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 |
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Authors | |
Issue Date | 2006 |
Publisher | American 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? |
Abstract | The 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 Identifier | http://hdl.handle.net/10722/168011 |
ISSN | 2021 Impact Factor: 3.837 2020 SCImago Journal Rankings: 1.231 |
ISI Accession Number ID | |
References |
DC Field | Value | Language |
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dc.contributor.author | Li, GY | en_HK |
dc.contributor.author | Zhang, J | en_HK |
dc.contributor.author | Chan, PWH | en_HK |
dc.contributor.author | Xu, ZJ | en_HK |
dc.contributor.author | Zhu, N | en_HK |
dc.contributor.author | Che, CM | en_HK |
dc.date.accessioned | 2012-10-08T03:14:05Z | - |
dc.date.available | 2012-10-08T03:14:05Z | - |
dc.date.issued | 2006 | en_HK |
dc.identifier.citation | Organometallics, 2006, v. 25 n. 7, p. 1676-1688 | en_HK |
dc.identifier.issn | 0276-7333 | en_HK |
dc.identifier.uri | http://hdl.handle.net/10722/168011 | - |
dc.description.abstract | The 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.language | eng | en_US |
dc.publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/organometallics | en_HK |
dc.relation.ispartof | Organometallics | en_HK |
dc.title | 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 | en_HK |
dc.type | Article | en_HK |
dc.identifier.email | Zhu, N: nzhu@hkucc.hku.hk | en_HK |
dc.identifier.email | Che, CM: cmche@hku.hk | en_HK |
dc.identifier.authority | Zhu, N=rp00845 | en_HK |
dc.identifier.authority | Che, CM=rp00670 | en_HK |
dc.description.nature | link_to_subscribed_fulltext | en_US |
dc.identifier.doi | 10.1021/om051009i | en_HK |
dc.identifier.scopus | eid_2-s2.0-33645813799 | en_HK |
dc.identifier.hkuros | 121170 | - |
dc.relation.references | http://www.scopus.com/mlt/select.url?eid=2-s2.0-33645813799&selection=ref&src=s&origin=recordpage | en_HK |
dc.identifier.volume | 25 | en_HK |
dc.identifier.issue | 7 | en_HK |
dc.identifier.spage | 1676 | en_HK |
dc.identifier.epage | 1688 | en_HK |
dc.identifier.isi | WOS:000236288100019 | - |
dc.publisher.place | United States | en_HK |
dc.identifier.scopusauthorid | Li, GY=15765581300 | en_HK |
dc.identifier.scopusauthorid | Zhang, J=16148295400 | en_HK |
dc.identifier.scopusauthorid | Chan, PWH=13607033800 | en_HK |
dc.identifier.scopusauthorid | Xu, ZJ=8708548900 | en_HK |
dc.identifier.scopusauthorid | Zhu, N=7201449530 | en_HK |
dc.identifier.scopusauthorid | Che, CM=7102442791 | en_HK |
dc.identifier.issnl | 0276-7333 | - |