TY - JOUR
T1 - Transition Metal-Catalyzed Intramolecular Cyclization of 1,5- And 1,6-Dienes via Direct Cleavage and Addition of the Carbon-Hydrogen Bond
AU - Fujii, Naoaki
AU - Kakiuchi, Fumitoshi
AU - Yamada, Airi
AU - Chatani, Naoto
AU - Murai, Shinji
PY - 1998/1
Y1 - 1998/1
N2 - Ruthenium- and rhodium-catalyzed intramolecular C-H/olefin coupling reactions of 1-(2-pyridyl)-, 1-(2-imidazolyl-, and 1-(2-oxazolyl)-1,5-dienes proceeded in a regiospecific manner to give 5-membered ring products. Their 1,6-diene analogues are also applicable to the cyclization reaction to give the corresponding 5- and 6-membered carbocycles. For the cyclization of the pyridine derivatives, [RhCl(PPh3)3] showed the highest catalytic activity with respect to efficiency and selectivity. When the imidazole derivatives were employed to the cyclization reaction, the combination of the rhodium(I) complex and the relatively sterically bulky phosphine (e.g., PCy3 and PPFOMe) was a quite effective catalyst system. In the case of the oxazoles, the ruthenium complex, [Ru(H)2(CO)(PPh3)3], showed the highest activity among the catalysts examined. These catalytic reactions usually proceed at 120°C. The [RhCl(PPh3)3]-catalyzed cyclization reaction of 2-[(1E)-4,4-dimethyl-1,5-hexadienyl]pyridine smoothly proceeded even at room temperature to give the corresponding cyclized product in 93% yield after 24 h. A hybrid catalyst system containing the rhodium(I) and both PPh3 and P(o-tolyl)3 had a slightly better catalytic activity compared with that of [RhCl(PPh3)3]. The intramolecular cyclization can be also applied to the C-H/CO/olefin coupling reactions. These carbonylation reactions gave the 5-membered ring ketones exclusively. The intramolecular C-H/olefin coupling reactions provide a new entry for constructing carbocyclic compounds from 1,n-dienes.
AB - Ruthenium- and rhodium-catalyzed intramolecular C-H/olefin coupling reactions of 1-(2-pyridyl)-, 1-(2-imidazolyl-, and 1-(2-oxazolyl)-1,5-dienes proceeded in a regiospecific manner to give 5-membered ring products. Their 1,6-diene analogues are also applicable to the cyclization reaction to give the corresponding 5- and 6-membered carbocycles. For the cyclization of the pyridine derivatives, [RhCl(PPh3)3] showed the highest catalytic activity with respect to efficiency and selectivity. When the imidazole derivatives were employed to the cyclization reaction, the combination of the rhodium(I) complex and the relatively sterically bulky phosphine (e.g., PCy3 and PPFOMe) was a quite effective catalyst system. In the case of the oxazoles, the ruthenium complex, [Ru(H)2(CO)(PPh3)3], showed the highest activity among the catalysts examined. These catalytic reactions usually proceed at 120°C. The [RhCl(PPh3)3]-catalyzed cyclization reaction of 2-[(1E)-4,4-dimethyl-1,5-hexadienyl]pyridine smoothly proceeded even at room temperature to give the corresponding cyclized product in 93% yield after 24 h. A hybrid catalyst system containing the rhodium(I) and both PPh3 and P(o-tolyl)3 had a slightly better catalytic activity compared with that of [RhCl(PPh3)3]. The intramolecular cyclization can be also applied to the C-H/CO/olefin coupling reactions. These carbonylation reactions gave the 5-membered ring ketones exclusively. The intramolecular C-H/olefin coupling reactions provide a new entry for constructing carbocyclic compounds from 1,n-dienes.
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U2 - 10.1246/bcsj.71.285
DO - 10.1246/bcsj.71.285
M3 - Article
AN - SCOPUS:0004746026
VL - 71
SP - 285
EP - 298
JO - Bulletin of the Chemical Society of Japan
JF - Bulletin of the Chemical Society of Japan
SN - 0009-2673
IS - 1
ER -