TY - JOUR
T1 - Chiral (iminophosphoranyl)ferrocenes
T2 - A new class of practical ligands for rhodium-catalyzed asymmetric hydrogenation
AU - Co, Thanh Thien
AU - Shim, Sang Chul
AU - Cho, Chan Sik
AU - Kim, Tae Jeong
AU - Kang, Sang Ook
AU - Han, Won Sik
AU - Ko, Jaejung
AU - Kim, Chung Kyun
PY - 2005/9/26
Y1 - 2005/9/26
N2 - A series of new chiral (iminophosphoranyl)ferrocenes, {η5- C5H4-(PPh2=N-2,6-R2-C 6H3)}-Fe{η5-C5H 3-1-PPh2-2-CH(Me)(Y)} (1a, Y = NMe2, R = Me; 1b, Y = NMe2, R = iPr; 1c, Y = OMe, R = iPr), {η5-C5H4-(PPh2=N-2,6-R 2-C6H3)}Fe{η5-C 5H3-1-(PPh2=N-2,6-R2-C 6H3)-2-CH-(Me)(Y)} (2a, R = Me, Y = NMe2; 2b, R = iPr, Y = NMe2,; 2c, R = Me, Y = OMe), and (η5-C5H5)Fe{η5-C 5H4-1-PR2-2-CH(Me)N=PPh3} (3a, R = Ph; 3b, R = C6H11), have been prepared from the reaction of 1,1′-bis(diphenylphosphino)-2-[(dimethylamino)ethyl]ferrocene with aryl azides (1 and 2) and the reaction of phosphine dichlorides (R 3PCl2) with 1,1′-bis-(diphenylphosphino)-2- (aminoethyl)ferrocene (3), respectively. They form rhodium complexes of the type [Rh(NBD)(L)]ClO4 (4-6; L = 1-3), where the ligand (L) adopts an η2(N,N) (2) or η2(P,N) mode (3), as expected. In the case of 1, a potential tridentate species, however, a chelating bidentate mode through the -CH(Me)NMe2 and -PPh2 groups is realized with the exclusion of the -P=NAr group from the coordination sphere, as confirmed by the X-ray crystal structure of [Rh(NBD)(1b)]ClO4 (4b). The new ligands (1-3) exhibit exceptionally high enantioselectivity (up to 99%) and catalytic activity in the Rh-catalyzed asymmetric hydrogenation of (E)-2-methylcinnamic acid, (Z)-2-acetamidocinnamate, and (Z)-2- acetamidoacrylate.
AB - A series of new chiral (iminophosphoranyl)ferrocenes, {η5- C5H4-(PPh2=N-2,6-R2-C 6H3)}-Fe{η5-C5H 3-1-PPh2-2-CH(Me)(Y)} (1a, Y = NMe2, R = Me; 1b, Y = NMe2, R = iPr; 1c, Y = OMe, R = iPr), {η5-C5H4-(PPh2=N-2,6-R 2-C6H3)}Fe{η5-C 5H3-1-(PPh2=N-2,6-R2-C 6H3)-2-CH-(Me)(Y)} (2a, R = Me, Y = NMe2; 2b, R = iPr, Y = NMe2,; 2c, R = Me, Y = OMe), and (η5-C5H5)Fe{η5-C 5H4-1-PR2-2-CH(Me)N=PPh3} (3a, R = Ph; 3b, R = C6H11), have been prepared from the reaction of 1,1′-bis(diphenylphosphino)-2-[(dimethylamino)ethyl]ferrocene with aryl azides (1 and 2) and the reaction of phosphine dichlorides (R 3PCl2) with 1,1′-bis-(diphenylphosphino)-2- (aminoethyl)ferrocene (3), respectively. They form rhodium complexes of the type [Rh(NBD)(L)]ClO4 (4-6; L = 1-3), where the ligand (L) adopts an η2(N,N) (2) or η2(P,N) mode (3), as expected. In the case of 1, a potential tridentate species, however, a chelating bidentate mode through the -CH(Me)NMe2 and -PPh2 groups is realized with the exclusion of the -P=NAr group from the coordination sphere, as confirmed by the X-ray crystal structure of [Rh(NBD)(1b)]ClO4 (4b). The new ligands (1-3) exhibit exceptionally high enantioselectivity (up to 99%) and catalytic activity in the Rh-catalyzed asymmetric hydrogenation of (E)-2-methylcinnamic acid, (Z)-2-acetamidocinnamate, and (Z)-2- acetamidoacrylate.
UR - http://www.scopus.com/inward/record.url?scp=26444445018&partnerID=8YFLogxK
U2 - 10.1021/om058028c
DO - 10.1021/om058028c
M3 - Article
AN - SCOPUS:26444445018
SN - 0276-7333
VL - 24
SP - 4824
EP - 4831
JO - Organometallics
JF - Organometallics
IS - 20
ER -