Activation of Propargylic Alcohols Derived from Hormonal Steroids by the Indenyl-Ruthenium(II) Complex [RuCl(5-C9
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- 作者：Victorio Cadierno ; Salvador Conejero ; M. Pilar Gamasa ; José ; Gimeno ; and Miguel A. Rodrí ; guez
- 刊名：Organometallics
- 出版年：2002
- 出版时间：January 7, 2002
- 年：2002
- 卷：21
- 期：1
- 页码：203 - 209
- 全文大小：111K
- 年卷期：v.21,no.1(January 7, 2002)
- ISSN：1520-6041
文摘
The indenyl-ruthenium(II) complex [RuCl(
5-C9H7)(PPh3)2] (1) reacts with ethisterone(2a), 17
-ethynylestradiol (2b), and mestranol (2c), in methanol and in the presence of NaPF6,to afford equilibrium mixtures containing the corresponding allenylidene 3a-c andvinylvinylidene 4a-c tautomers. Deprotonation of these mixtures with K2CO3 allows thepreparation of 
-enynyl derivatives 5a-c, which can be selectively alkylated with MeOSO2CF3 to yield disubstituted vinylvinylidene complexes 6a-c. Displacement of these equilibriums can also be accomplished by treatment of the reaction mixtures with acetonitrile orPMe2Ph. Thus, while in the first case terminal 1,3-enynes 7a-c are selectively obtained bydemetalation of vinylvinylidenes 4a-c, phosphonio-alkynyl complexes 9a-c are exclusivelyformed in the second case as the result of the nucleophilic addition of PMe2Ph on theelectrophilic C
atom of allenylidenes 3a-c. Ab initio molecular orbital calculations on themodels [Ru{=C=C=C(H)CH3}(5-C5H5)(PH3)2]+ and [Ru{=C=C(H)CH=CH2}(5-C5H5)(PH3)2]+ show that the vinylvinylidene tautomer is only 2.1 kcal/mol more stable than theallenylidene. The spontaneous tautomerization process between both complexes, whichinvolves a [1,3]-hydrogen sigmatropic rearrangement, requires an activation energy of 66.5kcal/mol.
5-C9H7)(PPh3)2] (1) reacts with ethisterone(2a), 17-ethynylestradiol (2b), and mestranol (2c), in methanol and in the presence of NaPF6,to afford equilibrium mixtures containing the corresponding allenylidene 3a-c andvinylvinylidene 4a-c tautomers. Deprotonation of these mixtures with K2CO3 allows thepreparation of -enynyl derivatives 5a-c, which can be selectively alkylated with MeOSO2CF3 to yield disubstituted vinylvinylidene complexes 6a-c. Displacement of these equilibriums can also be accomplished by treatment of the reaction mixtures with acetonitrile orPMe2Ph. Thus, while in the first case terminal 1,3-enynes 7a-c are selectively obtained bydemetalation of vinylvinylidenes 4a-c, phosphonio-alkynyl complexes 9a-c are exclusivelyformed in the second case as the result of the nucleophilic addition of PMe2Ph on theelectrophilic C atom of allenylidenes 3a-c. Ab initio molecular orbital calculations on themodels [Ru{=C=C=C(H)CH3}(5-C5H5)(PH3)2]+ and [Ru{=C=C(H)CH=CH2}(5-C5H5)(PH3)2]+ show that the vinylvinylidene tautomer is only 2.1 kcal/mol more stable than theallenylidene. The spontaneous tautomerization process between both complexes, whichinvolves a [1,3]-hydrogen sigmatropic rearrangement, requires an activation energy of 66.5kcal/mol.