Synthese und Charakterisierung neuer Acetylenkomplexe des Mangans und Rheniums
作者:Helmut G. Alt、Heidi E. Engelhardt
DOI:10.1016/s0022-328x(00)99460-9
日期:1988.3
The reaction of the photochemically-generated tetrahydrofuran complexes Cp′(CO)2M(thf) (Cp′ η5-C5H5, η5-C5H4Me, η5-C5Me5; M Mn, Re) with various alkynes R1C2R2 (R1, R2 H, Me, Ph) yields are acetylene complexes Cp′(CO)2MR1C2R2. These compounds were identified from their IR, 1H NMR, 13C NMR and mas spectra.
光化学产生的四氢呋喃络合物Cp的反应'(CO)2 M(THF)(CP'η 5 -C 5 H ^ 5,η 5 -C 5 H ^ 4 Me中,η 5 -C 5我5 ; M带有各种炔烃R 1 C 2 R 2(R 1,R 2 H,Me,Ph)的Mn,Re)是乙炔配合物Cp'(CO)2 MR 1 C 2 R 2。这些化合物由其IR,1 H NMR,13鉴定13 C NMR和mas光谱。
Casey, Charles P.; Yi, Chae S., Journal of the American Chemical Society, 1992, vol. 114, p. 6597 - 6598
作者:Casey, Charles P.、Yi, Chae S.
DOI:——
日期:——
Synthesis of η<sup>3</sup>-Propargyl Rhenium Complexes
作者:Charles P. Casey、Anthony D. Selmeczy、John R. Nash、Chae S. Yi、Douglas R. Powell、Randy K. Hayashi
DOI:10.1021/ja960375d
日期:1996.1.1
Hybride abstraction from eta(2)-alkyne rhenium complexes C(5)Me(5)(CO)(2)Re(RC=CR') (2) with Ph(3)C(+)PF(6)(-) produces eta(3)-propargyl complexes C(5)Me(5)(CO)(2)Re(eta(3)-CHR ''-C=CR)(PF6-)-P-+ (3). Successful hydride abstraction to produce eta(3)-propargyl complexes was observed only for internal acetylenes with a methyl or primary alkyl substituent. an unusual regioselectivity for hydride abstraction was observed: CH3CH2>CH3 much greater than CH(CH3)(2). Hydride abstraction from diethylacetylene complex C(5)Me(5)(CO)(2)Re(eta(2)-CH3CH2C=CCH2CH3) (2c) produced a single stereoisomer of eta(3)-propargyl complex C(5)Me(5)(CO)(2)Re(eta(3)-CH3CH-C=CCH2CH3)(PF6-)-P-+ (3c) in which it is suggested that the methyl group is located in the less crowded position anti to the Cp* group. the regio- and stereoselectivity of hydride abstraction can be explained in terms of transition stat A in which the carbon hydrogen bond being cleaved is antiperiplanar with respect to rhenium and the syn propargylic substituent comes into close contact with the Cp* ligand. Protonation of C(5)Me(5)(CO)(2)Re(eta(2)-HC=CCH2OH) (6h) with HBF4-Et(2)O gave C(5)Me(5)(CO)(2)Re(eta(3)-CH2-Me(5)(CO)(2)Re(eta(2)-HC=CCH3) (2h). Protonation of propargyl alcohol complexes provides a regiospecific synthesis of pi-propargyl complexes: protonation of C(5)Me(5)(CO)(2)Re(eta(2)-CH3CH2C=CCH2OH) (6e) gave C(5)Me(5)(CO)(2)Re(eta(3)-CH2-C=CCH2CH3)(BF4-)-B-+ (3c-BF4), while protonation of C(5)Me(5)(CO)(2)Re[eta(2)-CH3C=CCH(CH3)OH] (6d) gave C-5-Me(5)(CO)(2)Re(eta(3)-CH3CH-C=CCH3)(BF4-)-B-+ (anti-ed-BF4).
Acid-Catalyzed Isomerization of Rhenium Alkyne Complexes to Rhenium Allene Complexes via 1-Metallacyclopropene Intermediates
作者:Charles P. Casey、John T. Brady
DOI:10.1021/om980348r
日期:1998.10.1
The alkyne complexes C5Me5(CO)(2)Re(eta(2)-MeC=CMe) (1) and C5H5(CO)(2)Re(eta(2)-MeC=CMe) (6) underwent acid-catalyzed isomerization by way of 1-metallacyclopropene intermediates to form the allene complexes C5Me5(CO)(2)Re(eta(2)-2,3-MeHC=C=CH2) (5) and C5H5(CO)(2)Re(eta(2)-2,3-MeHC=C=CH2) (7). Stoichiometric reaction of 1 with CF3CO2H initially produced the kinetic addition product C5Me5(CO)(2)Re[eta(2)-(Z)-MeHC=CMeO2CCF3] (8-Z), which slowly isomerized to the thermodynamically more stable E isomer 8-E. The reaction of 6 with CF3CO2H at -73 degrees C produced only C5H5(CO)(2)Re[eta(2)-(E)-MeHC=CMeO2CCF3] (9-E), which isomerized at -60 degrees C to a 80:20 equilibrium mixture of 9-E and 9-Z. Treatment of 9-E and 9-Z with base led to formation of allene complex 7. The rate of this elimination was independent of base concentration. Labeling studies showed that the 1-metallacyclopropene intermediate C5H5(CO)(2)Re(eta(2)-CMeCHMe)+CF3CO2- (12-CF3CO2) undergoes a number of important reactions which include, in order of decreasing relative rates: (1) addition of trifluoroacetate to give enol trifluoroacetate complexes, (2) deprotonation to give complexed allenes, (3) degenerate 1,2-hydride migrations, (4) hydride migrations to give eta(3)-allyl complexes, and (5) deprotonation to give complexed alkynes.
Ligand Additions to Cp*(CO)<sub>2</sub>ReRe(CO)<sub>2</sub>Cp* and Fragmentation and Rearrangement Reactions of Cp*(CO)<sub>2</sub>Re(μ-CO)Re(CO)(L)Cp*
作者:Charles P. Casey、Ronald S. Cariño、Hiroyuki Sakaba、Randy K. Hayashi
DOI:10.1021/om9509507
日期:1996.5.28
Reaction of Cp*(CO)2ReRe(CO)2Cp* (1) with CO produced the stable adduct Cp*(CO)2Re(μ-CO)Re(CO)2Cp* (2). Reaction of 1 with CH3CN gave the stable adduct Cp*(CO)2Re(μ-CO)Re(CO)(CH3CN)Cp* (6). Reaction of 1 with PMe3 or CH2CH2 at low temperature produced the adducts Cp*(CO)2Re(μ-CO)Re(CO)(PMe3)Cp* (5) and Cp*(CO)2Re(μ-CO)Re(CO)(CH2CH2)Cp* (7), which fragment at −20 °C to Cp*Re(CO)2(THF) and either Cp*Re(CO)2(PMe3)