Preparation, structure, and reactions of stable mono(alkylthio)carbene iron complexes of the (.eta.5-C5H5)(CO)2Fe system

Knors, C.; Kuo, Gee Hong; Lauher, Joseph W.; Eigenbrot, Charles; Helquist, Paul

doi:10.1021/om00148a017

Cited by 39 publications

(9 citation statements)

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“…The topics selected are: isomerization reactions of terminal iron-alkenyl complexes [ 603 ], dimerization of (2,4-dimethylpentadienyl)iron tricarbonyl complexes [ 604 ], insertions of cyano- and dicyanoacetylenes into iron-hydride bonds [ 605 ], carbonyl insertion reactions and formation of [HFe(CO) 2 ] − , [(CO) 3 FeCHO] − , and [(CO) 4 FeCHO] − [ 606 ]; also, carbon dioxide fixation via [(η 5 -C 5 H 5 )Fe(CO) 2 ] − metalate Li + or Na + salts [ 607 ], reaction of salt

with cyclopropylmethyl bromide [ 608 ], and reaction of [η 5 -O-dichlorobenzene-(η 5 -C 5 H 5 )iron] +

with phenol [ 609 ]. Also covered are reactions of (η 5 -C 5 H 5 )Fe(CO) 2 (η 1 -C 5 H 5 ) with bis(tri-fluoromethyl) ketene (to give the 2:1 adducts) [ 610 ], reactions of stable mono(alkylthio)carbene complexes of the (η 5 -C 5 H 5 )Fe(CO) 2 system [ 611 ], conversion of a diiron μ-ketone complex into a binuclear cationic complex [ 612 ], and reaction of a diiron bridging methylidene complex with an ethylidene complex [ 613 ]. Further new reactions are: reaction of [(η 2 -C 5 H 5 )Fe(CO) 2 ] 2 (η-C=CH 2 ) with HC≡CCN [ 614 ], reaction of

with 1,4-dithiane [ 615 ], reaction of [Fe 2 (η 2 -C 5 H 5 )(CO) 2 (CNMe)CN(Me)H] + with Ag(I) salts [ 616 ], reaction of [Fe 2 (η-C 5 H 5 ) 2 (CO) 4− n (CNMe) n ( n = O−4) complexes with halogens and mercury(II) salts [ 617 ], reaction of Fe(CO) 5 with N,N -diethyl- S -ethylcarbamate [ 618 ], also, the reaction of Fe 3 (CO) 12 or Fe 2 (CO) 9 with 1-diethylaminopropyne [ 619 ], the reactivity of [HFe 3 (CO) 11 ] − toward alkynes [ ...…”

Section: Miscellaneous Recent Resultsmentioning

confidence: 99%

New chemical and stereochemical applications of organoiron complexes

Fatiadi

1991

J. RES. NATL. INST. STAN.

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The objective of this review is to provide a current overview of the rapidly developing chemistry of organometallic complexes and particularly organoiron complexes useful in asymmetric and stereoselective reactions. Also covered are stereoselective reactions of α, β-unsaturated acyl ligands bound to the chiral auxiliary [(η5-C5H5) Fe(CO)(PPh3)] and new applications of organoiron complexes in the synthesis of natural products. The mechanistic aspects and stabilizing effects of the Fe(CO)3 group for alkenes or conjugated dienes are discussed. A brief summary of recent work on the special role of iron in biological reactions is also included.

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with cyclopropylmethyl bromide [ 608 ], and reaction of [η 5 -O-dichlorobenzene-(η 5 -C 5 H 5 )iron] +

Section: Miscellaneous Recent Resultsmentioning

confidence: 99%

New chemical and stereochemical applications of organoiron complexes

Fatiadi

1991

J. RES. NATL. INST. STAN.

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“…The observation of equivalent i Pr substituents is consistent with the structure of the related neutral system [CpV(CO) 3 BN(SiMe 3 ) 2 ]5c and agrees with the results of DFT calculations for the model compounds [(η 5 ‐C 5 R 5 )Fe(CO) 2 (BNMe 2 )] + (R=H, Me), for which a minimum‐energy structure close to C s symmetry [< centroid‐Fe‐N‐C≈90° (84.6° for R=Me)] and a low barrier to rotation about the Fe‐B‐N axis (≈2.2 kcal mol −1 ) have been calculated 7b,c. Furthermore, the IR spectrum of 3 shows carbonyl stretching frequencies ($\tilde \nu $ =2070, 2028 cm −1 ) that are significantly blue shifted with respect to 2 ($\tilde \nu $ =2001, 1941 cm −1 ) (Δ$\tilde \nu $ ≈50 cm −1 for [Cp*Fe(CO) 2 {B(Mes)Cl}]/[Cp*Fe(CO) 2 (BMes)] + ) and are very similar to those reported for the archetypal Fischer carbene systems such as [CpFe(CO) 2 CH(SPh)] + (PF 6 ) − ($\tilde \nu $ =2073, 2034 cm −1 ) 9. Further evidence for the nature of 3 was obtained: 1) from the reaction of 3 with ppnCl (see Supporting Information), which like the analogous reaction for structurally characterized cationic derivatives,6b, 7 generates a haloboryl complex (in this case 2 ) by the addition of a halide at boron and 2) from the reaction of 3 with Ph 3 PO, which proceeds via the structurally characterized adduct [CpFe(CO) 2 {B(N i Pr 2 )(OPPh 3 )}] + (BAr f 4 ) − (see below).…”

Section: Methodsmentioning

confidence: 99%

Cationic Terminal Borylene Complexes: A Synthetic and Mechanistic Investigation of MB Metathesis Chemistry

Kays¹,

Day²,

Ooi³

et al. 2005

Angew Chem Int Ed

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Metathesis reactions constitute a key component of modern synthetic chemistry; olefin metathesis, for example, provides a versatile and widely exploited carbon-carbon bond-forming methodology.[1] Such reactions are typically catalyzed by organometallic complexes that contain M=C bonds.[2] The synthesis of analogous complexes that contain M=Si bonds, for example, has led to an in-depth investigation of their reactivity towards unsaturated substrates. [3] Synthetic approaches that lead to the isolation of related systems with M = B bonds have been developed only recently: [4][5][6][7] for example, halide-abstraction chemistry gives access to cationic terminal borylene complexes, [L n M= BX][7] Consequently, reports of the fundamental chemistry of M=B bonds are somewhat limited (predominantly to metal-metal transfer reactions and addition/substitution reactivity towards nucleophiles). [4,6,7] Thus, the chemistry of [Cp*Fe(CO) 2 (BMes)] + (Mes = mesityl = 2,4,6-Me 3 C 6 H 2 , Cp* = pentamethylcyclopentadienyl), for example, is dominated by the electrophilic character at both the Fe and B centers. [7] In an attempt to tune the reactivity of these highly unsaturated complexes we investigated the synthesis of cationic aminoborylene systems, [L n M = BNR 2 ]+ .[5] Chloride abstraction from [CpFe(CO) 2 {B(NiPr 2 )Cl}] (2) (Cp = cyclopentadienyl) by Na(BAr À . The steric bulk of the amino substituents is a key point: the use of the smaller NMe 2 group results in the formation of a thermally fragile borylene product in the subsequent halide-abstraction step, [7b, 8] whereas [CpFe(CO) 2 {B(tmp)Cl}] (tmp = tetramethylpiperamino) was inaccessible from tmpBCl 2 . Compound 2 is a pale yellow sublimable crystalline solid, which was characterized by multinuclear NMR and IR spectroscopy, mass spectrometry, and X-ray crystallographic analysis (Figure 1).The reaction of 2 with Na(BAr f 4 ) in dichloromethane results in a quantitative conversion (determined by 1 H and 11 B NMR spectroscopy) into 3. The latter product (along with the C 5 H 4 Me analogue) is a colourless oil at (or close to) room temperature, but its formulation can be definitively established from spectroscopic and reactivity data. The measured 11 B chemical shift for 3 (d B = 93.5 ppm) is very close to that reported by Braunschweig et al. for neutral terminal-aminoborylene systems of the type L n M=BN(SiMe 3 ) 2 (d B = 86.6-98.3 ppm).[5] The downfield shift upon chloride abstraction (Dd B = 38.1 between 2 and 3) mirrors that found for and 88.0 ppm, respectively). [7,8] The 1 H and 13 C NMR data are

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“…Precursor molecules for the study of cationic carbene cyclization reactions [78][79][80][81][82][83][84] are available, e.g. from appropriate bromides, such as 127 via the corresponding Grignard reagents that undergo 1,2-addition reactions to the cationic thiocarbene complex 126 in yields up to 95%.…”

Section: Scheme 38mentioning

confidence: 99%

“…from appropriate bromides, such as 127 via the corresponding Grignard reagents that undergo 1,2-addition reactions to the cationic thiocarbene complex 126 in yields up to 95%. 78,79,83 Complex 126 was obtained by treatment of 119a with tritylium hexafluorophosphate (Scheme 39).…”

Section: Scheme 38mentioning

confidence: 99%