Unusual Pathways for Metal-Assisted C-C and C-P Coupling Reactions Using Allenylidenerhodium Complexes as Precursors
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- 作者：Helmut Werner ; Ralf Wiedemann ; Matthias Laubender ; Bettina Windmü ; ller ; Paul Steinert ; Olaf Gevert ; and Justin Wolf
- 刊名：Journal of the American Chemical Society
- 出版年：2002
- 出版时间：June 19, 2002
- 年：2002
- 卷：124
- 期：24
- 页码：6966 - 6980
- 全文大小：254K
- 年卷期：v.124,no.24(June 19, 2002)
- ISSN：1520-5126
文摘
The rhodium allenylidenes trans-[RhCl{=C=C=C(Ph)R}(PiPr3)2] [R = Ph (1), p-Tol (2)] reactwith NaC5H5 to give the half-sandwich type complexes [(
5-C5H5)Rh{=C=C=C(Ph)R}(PiPr3)] (3, 4). Thereaction of 1 with the Grignard reagent CH2=CHMgBr affords the 3-pentatrienyl compound [Rh(3-CH2CHC=C=CPh2)(PiPr3)2] (6), which in the presence of CO rearranges to the 1-pentatrienyl derivativetrans-[Rh{1-C(CH=CH2)=C=CPh2}(CO)(PiPr3)2] (7). Treatment of 7 with acetic acid generates thevinylallene CH2=CH-CH=C=CPh2 (8). Compounds 1 and 2 react with HCl to give the five-coordinateallenylrhodium(III) complexes [RhCl2{CH=C=C(Ph)R}(PiPr3)2] (10, 11). An unusual [C3 + C2 + P] couplingprocess takes place upon treatment of 1 with terminal alkynes HC
CR', leading to the formation of the3-allylic compounds [RhCl{3-anti-CH(PiPr3)C(R')C=C=CPh2}(PiPr3)] [R' = Ph (12), p-Tol (13), SiMe3(14)]. From 12 and RMgBr the corresponding phenyl and vinyl rhodium(I) derivatives 15 and 16 have beenobtained. The previously unknown unsaturated ylide iPr3PCHC(Ph)=C=C=CPh2 (17) was generated from12 and CO. A [C3 + P] coupling process occurs on treatment of the rhodium allenylidenes 1, 2, and trans-[RhCl{=C=C=C(p-Anis)2}(PiPr3)2] (20) with either Cl2 or PhICl2, affording the ylide-rhodium(III) complexes[RhCl3{C(PiPr3)C=C(R)R'}(PiPr3)] (21-23). The butatrienerhodium(I) compounds trans-[RhCl{2-H2C=C=C=C(R)R'}(PiPr3)2] (28-31) were prepared from 1, 20, and trans-[RhCl{=C=C=C(Ph)R}(PiPr3)2] [R= CF3 (26), tBu (27)] and diazomethane; with the exception of 30 (R = CF3, R' = Ph), they thermallyrearrange to the isomers trans-[RhCl{2-H2C=C=C=C(R)R'}(PiPr3)2] (32, 33, and syn/anti-34). The new1,1-disubstituted butatriene H2C=C=C=C(tBu)Ph (35) was generated either from 31 or 34 and CO. Theiodo derivatives trans-[RhI(2-H2C=C=C=CR2)(PiPr3)2] [R = Ph (38), p-Anis (39)] were obtained by anunusual route from 1 or 20 and CH3I in the presence of KI. While the hydrogenation of 1 and 26 leads tothe allenerhodium(I) complexes trans-[RhCl{2-H2C=C=C(Ph)R}(PiPr3)2] (40, 41), the thermolysis of 1and 20 produces the rhodium(I) hexapentaenes trans-[RhCl(2-R2C=C=C=C=C=CR2)(PiPr3)2] (44, 45)via C-C coupling. The molecular structures of 3, 7, 12, 21, and 28 have been determined by X-raycrystallography. (Abbreviations used: p-Tol = p-tolyl, 4-C6H4CH3; p-Anis = p-anisyl, 4-C6H4OCH3.)
5-C5H5)Rh{=C=C=C(Ph)R}(PiPr3)] (3, 4). Thereaction of 1 with the Grignard reagent CH2=CHMgBr affords the 3-pentatrienyl compound [Rh(3-CH2CHC=C=CPh2)(PiPr3)2] (6), which in the presence of CO rearranges to the 1-pentatrienyl derivativetrans-[Rh{1-C(CH=CH2)=C=CPh2}(CO)(PiPr3)2] (7). Treatment of 7 with acetic acid generates thevinylallene CH2=CH-CH=C=CPh2 (8). Compounds 1 and 2 react with HCl to give the five-coordinateallenylrhodium(III) complexes [RhCl2{CH=C=C(Ph)R}(PiPr3)2] (10, 11). An unusual [C3 + C2 + P] couplingprocess takes place upon treatment of 1 with terminal alkynes HCCR', leading to the formation of the3-allylic compounds [RhCl{3-anti-CH(PiPr3)C(R')C=C=CPh2}(PiPr3)] [R' = Ph (12), p-Tol (13), SiMe3(14)]. From 12 and RMgBr the corresponding phenyl and vinyl rhodium(I) derivatives 15 and 16 have beenobtained. The previously unknown unsaturated ylide iPr3PCHC(Ph)=C=C=CPh2 (17) was generated from12 and CO. A [C3 + P] coupling process occurs on treatment of the rhodium allenylidenes 1, 2, and trans-[RhCl{=C=C=C(p-Anis)2}(PiPr3)2] (20) with either Cl2 or PhICl2, affording the ylide-rhodium(III) complexes[RhCl3{C(PiPr3)C=C(R)R'}(PiPr3)] (21-23). The butatrienerhodium(I) compounds trans-[RhCl{2-H2C=C=C=C(R)R'}(PiPr3)2] (28-31) were prepared from 1, 20, and trans-[RhCl{=C=C=C(Ph)R}(PiPr3)2] [R= CF3 (26), tBu (27)] and diazomethane; with the exception of 30 (R = CF3, R' = Ph), they thermallyrearrange to the isomers trans-[RhCl{2-H2C=C=C=C(R)R'}(PiPr3)2] (32, 33, and syn/anti-34). The new1,1-disubstituted butatriene H2C=C=C=C(tBu)Ph (35) was generated either from 31 or 34 and CO. Theiodo derivatives trans-[RhI(2-H2C=C=C=CR2)(PiPr3)2] [R = Ph (38), p-Anis (39)] were obtained by anunusual route from 1 or 20 and CH3I in the presence of KI. While the hydrogenation of 1 and 26 leads tothe allenerhodium(I) complexes trans-[RhCl{2-H2C=C=C(Ph)R}(PiPr3)2] (40, 41), the thermolysis of 1and 20 produces the rhodium(I) hexapentaenes trans-[RhCl(2-R2C=C=C=C=C=CR2)(PiPr3)2] (44, 45)via C-C coupling. The molecular structures of 3, 7, 12, 21, and 28 have been determined by X-raycrystallography. (Abbreviations used: p-Tol = p-tolyl, 4-C6H4CH3; p-Anis = p-anisyl, 4-C6H4OCH3.)