Ru(II)-Catalyzed Cycloadditions of 1,6-Heptadiynes with Alkenes: New Synthetic Potential of Ruthenacyclopentatrienes as Biscarbenoids in Tandem Cyclopropanation of Bicycloalkenes and Heteroatom-Assist
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- 作者：Yoshihiko Yamamoto ; Hideaki Kitahara ; Ryuji Ogawa ; Hiroyuki Kawaguchi ; Kazuyuki Tatsumi ; and Kenji Itoh
- 刊名：Journal of the American Chemical Society
- 出版年：2000
- 出版时间：May 10, 2000
- 年：2000
- 卷：122
- 期：18
- 页码：4310 - 4319
- 全文大小：423K
- 年卷期：v.122,no.18(May 10, 2000)
- ISSN：1520-5126
文摘
The ruthenium(II)-catalyzed tandem cycloaddition of 1,6-heptadiynes with bicyclic alkenes, suchas bicyclo[3.2.1]heptenones and norbornene derivatives, furnishes the 1:2 adducts between the diynes and twomolecules of the bicycloalkenes together with common [2 + 2 + 2] cyclocotrimerization products. The structureof a representative tandem 1:2 adduct between dimethyl dipropargylmalonate and 2,4-dimethylbicyclo[3.2.1]oct-6-en-3-one was unequivocally determined by X-ray analysis and was concluded to involve an unusual1,2-dicyclopropylcyclopentene skeleton. On the basis of the spectroscopic analogy, the previously communicatedstructures of the tandem cycloadducts between the diynes and norbornene derivatives were corrected. Theformation of the tandem double-cyclopropanation products from the diynes is chemical evidence of a bis-carbenoid hybrid structure, 1,3,5-metallacyclopentatriene, of the corresponding 2,4-metallacyclopentadieneintermediates. The selectivity for the formation of the tandem cyclopropanation adducts was increased in theorder of (
5-C9H7)Ru(PPh3)2Cl > CpRu(cod)Cl > Cp*Ru(cod)Cl, indicative of the 5 
3 ring slippage ofthe cyclopentadienyl type ligands playing a key role in the tandem cyclopropanation. On the other hand, thenormal [2 + 2 + 2] cyclocotrimerization between 1,6-heptadiynes and alkenes was selectively catalyzed byCp*Ru(cod)Cl, in the case of cyclic or linear alkenes possessing heteroatoms at the allylic position. The latterheteroatom-assisted cyclocotrimerization was also catalyzed by a paramagnetic dinuclear ruthenium(III) complex,[Cp*RuCl2]2, at lower temperature.
5-C9H7)Ru(PPh3)2Cl > CpRu(cod)Cl > Cp*Ru(cod)Cl, indicative of the 5 3 ring slippage ofthe cyclopentadienyl type ligands playing a key role in the tandem cyclopropanation. On the other hand, thenormal [2 + 2 + 2] cyclocotrimerization between 1,6-heptadiynes and alkenes was selectively catalyzed byCp*Ru(cod)Cl, in the case of cyclic or linear alkenes possessing heteroatoms at the allylic position. The latterheteroatom-assisted cyclocotrimerization was also catalyzed by a paramagnetic dinuclear ruthenium(III) complex,[Cp*RuCl2]2, at lower temperature.