-Substituted Vinylidene, Chroman-2-ylidene, and Hexahydrochromen-2-ylidene from Ruthenium Allenylidene/Alkenylcarbyne Complexes
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- 作者：Emilio Bustelo ; Manuel Jimé ; nez-Tenorio ; M. Carmen Puerta ; Pedro Valerga
- 刊名：Organometallics
- 出版年：2007
- 出版时间：August 13, 2007
- 年：2007
- 卷：26
- 期：17
- 页码：4300 - 4309
- 全文大小：224K
- 年卷期：v.26,no.17(August 13, 2007)
- ISSN：1520-6041
文摘
The activation of 1-phenyl-2-propyn-1-ol, 1-(4-methoxyphenyl)-2-propyn-1-ol, and 1-(4-fluorophenyl)prop-2-yn-1-ol by [Cp*RuCl(dippe)] (dippe = 1,2-bis(diisopropylphosphine)ethane) provides a series ofallenylidene derivatives, [Cp*Ru(dippe)(=C=C=CHAr)][BF4] (Ar = C6H5 (1), p-C6H4(OMe) (2), p-C6H4(F) (3)), and the corresponding alkenylcarbyne complexes [Cp*Ru(dippe)(
C-CH=CHAr)][BF4]2 (Ar= C6H5 (4), p-C6H4(OMe) (5), p-C6H4(F) (6)) by allenylidene protonation. The dicationic alkenylcarbynecomplexes behave as a carbocationic species able to cause the aromatic electrophilic substitution of 1,3-dimethoxybenzene, furnishing 
-substituted vinylidene complexes [Cp*Ru{=C=CHCHAr(C6H3(OMe)2)}(dippe)][BF4] (Ar = C6H5 (7), p-C6H4(OMe) (8), p-C6H4(F) (9)). A series of bicyclic carbene complexes[Cp*Ru(L)(dippe)][BF4] (L = 7-hydroxy-4-phenylchroman-2-ylidene (10), 4-(4-methoxyphenyl)-7-hydroxychroman-2-ylidene (11), 4-(4-fluorophenyl)-7-hydroxychroman-2-ylidene (12)) are obtained bythe direct reaction of resorcinol with alkenylcarbyne complexes. The X-ray structure of 12 shows theformation of a chroman-2-ylidene ligand. The reaction of allenylidene complexes requires the presenceof a weak acid (NH4BF4) to perform the electrophilic aromatic substitution (step 1) and a strong acid(HBF4) to induce the intramolecular cyclization (step 2). The -substituted vinylidene [Cp*Ru{=C=CHCHPh(C6H3(OH)2)}(dippe)][BF4] (13) has been isolated as the intermediate between steps 1 and 2.Similar bicyclic carbon skeletons (hexahydrochromen-2-ylidene, complexes 14b-16b) are obtained byreaction of the allenylidene complexes with cyclohexanedione. In this case, the carbene complexes arein equilibrium with the isomeric -substituted vinylidenes 14a-16a. The effect of the presence of electron-donor and electron-withdrawing groups on the allenylidene/alkenylcarbyne substituents is analyzed.
C-CH=CHAr)][BF4]2 (Ar= C6H5 (4), p-C6H4(OMe) (5), p-C6H4(F) (6)) by allenylidene protonation. The dicationic alkenylcarbynecomplexes behave as a carbocationic species able to cause the aromatic electrophilic substitution of 1,3-dimethoxybenzene, furnishing -substituted vinylidene complexes [Cp*Ru{=C=CHCHAr(C6H3(OMe)2)}(dippe)][BF4] (Ar = C6H5 (7), p-C6H4(OMe) (8), p-C6H4(F) (9)). A series of bicyclic carbene complexes[Cp*Ru(L)(dippe)][BF4] (L = 7-hydroxy-4-phenylchroman-2-ylidene (10), 4-(4-methoxyphenyl)-7-hydroxychroman-2-ylidene (11), 4-(4-fluorophenyl)-7-hydroxychroman-2-ylidene (12)) are obtained bythe direct reaction of resorcinol with alkenylcarbyne complexes. The X-ray structure of 12 shows theformation of a chroman-2-ylidene ligand. The reaction of allenylidene complexes requires the presenceof a weak acid (NH4BF4) to perform the electrophilic aromatic substitution (step 1) and a strong acid(HBF4) to induce the intramolecular cyclization (step 2). The -substituted vinylidene [Cp*Ru{=C=CHCHPh(C6H3(OH)2)}(dippe)][BF4] (13) has been isolated as the intermediate between steps 1 and 2.Similar bicyclic carbon skeletons (hexahydrochromen-2-ylidene, complexes 14b-16b) are obtained byreaction of the allenylidene complexes with cyclohexanedione. In this case, the carbene complexes arein equilibrium with the isomeric -substituted vinylidenes 14a-16a. The effect of the presence of electron-donor and electron-withdrawing groups on the allenylidene/alkenylcarbyne substituents is analyzed.