Ferrocene studies. XVIII. Identification and stereochemistry of nine bimolecular Clemmensen reduction products of benzoylferrocene la--d

Goldberg, Stanley I.; Bailey, William D.; McGregor, M. L.

doi:10.1021/jo00805a006

Cited by 14 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…29,30,32 Depending on the nature of the reactants and the reaction conditions, the pinacolate can evolve toward the classic cross-coupling product 6 or toward other products, principally the transposition product 7. 33,34 For example, at THF reflux, we quantitatively obtained the olefin 6c, while at 0 °C, only the transposition product 7c was found after acid workup. This result is similar for the reaction with 4-hydroxybenzophenone, although a small quantity of the transposition product 7b was also isolated at reflux.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

Synthesis and Antiproliferative Effects of [3]Ferrocenophane Transposition Products and Pinacols Obtained from McMurry Cross-Coupling Reactions

et al. 2012

View full text Add to dashboard Cite

We here report the synthesis and antiproliferative activities of two new series of ferrocenophanes obtained from McMurry cross-coupling reactions of [3]ferrocenophan-1-one with benzophenone, 4-hydroxybenzophenone, 4,4′-dihydroxybenzophenone, and 4,4′-diacetylaminobenzophenone. In addition to the main formation of olefins at reflux, tetrahedral transposition products, resulting from a pinacolic rearrangement, were also isolated in about 10% yields. Lowering the temperature of the reaction to 0 °C allowed the isolation of pinacols, which could be transformed into transposition compounds in good yields. Three ferrocenophane compounds have been characterized by X-ray crystallography: 1-(p-hydroxyphenyl)-1-phenyl-2-oxo[4]ferrocenophane (7b), 1,1-diphenyl-2-oxo[4]ferrocenophane (7c), and 1-hydroxy-1-[1-hydroxy-1-[3]ferrocenophanyl][3]ferrocenophane (12) crystallize in monoclinic P21/n, triclinic P1̅, and monoclinic P21/c space groups, respectively. The antiproliferative effects on hormone-independent breast cancer cells (MDA-MB-231) of the transposition compounds are generally lower than those of their corresponding butene analogues (IC50 values in micromolar versus nanomolar range). In contrast and quite surprisingly, the pinacol complexes are significantly cytotoxic (IC50 in the nanomolar range), among the most cytotoxic ferrocene compounds prepared so far. This antiproliferative activity may be linked to their oxidative cleavage.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 95%

Synthesis and Antiproliferative Effects of [3]Ferrocenophane Transposition Products and Pinacols Obtained from McMurry Cross-Coupling Reactions

et al. 2012

View full text Add to dashboard Cite

show abstract

“…All proton and carbon signals of 2 and 3 have been assigned by 2D NMR spectroscopy, literature comparison [16] and simulation of the coupling patterns (H [22][23][24] , H [16][17][18][19] ). The amine protons of 3 resonate at d = 2.74 in CD 2 Cl 2 , almost independent of temperature and only slightly shifted to lower field as compared to those of aminoferrocene FcNH 2 (d = 2.63 [16]).…”

Section: Resultsmentioning

confidence: 99%

“…6). A follow-up reaction (probably pinacol formation [22][23][24][25][26][27]) is coupled to the reduction processes giving rise to new oxidation waves at 0.52 V and 0.16 V for 2 and 3, respectively. The electron accepting character of both substituents in 2 results in its quite positive oxidation potential.…”

Section: Resultsmentioning

confidence: 99%

Dynamic behaviour of 1,n′-disubstituted ferrocenes

Heinze¹,

Beckmann²

2006

Journal of Organometallic Chemistry

View full text Add to dashboard Cite

“…Early attempts to reduce benzoylferrocene by the Clemmensen procedure in (9-1-methoxy-2-methylbutane as chiral solvent led to complex mixtures of products with low enantiomeric excess [65]. All asymmetric syntheses of ferrocene derivatives known so far are reductions of ferrocenyl ketones or aldehydes to chiral secondary alcohols.…”

Section: By Asymmetric Synthesismentioning

confidence: 99%

Chiral Ferrocene Derivatives. An Introduction

Wagner¹,

Herrmann²

1994

Ferrocenes

View full text Add to dashboard Cite

Soon after its discovery, it was found, that ferrocene behaves in many respects like an aromatic electron-rich organic compound, which is activated towards electrophilic reactions almost like phenol. As a consequence, a rich organic chemistry of ferrocene was developed, in which the organometallic moiety is treated like a simple phenyl group. Thus, Friedel -Crafts acylation leads to ferrocenyl ketones, which can be reduced to secondary ferrocenyl alcohols containing an asymmetric carbon atom. Compounds of this type can be resolved into the enantiomers by standard resolution techniques [l] and do not provide any problems with respect to chemistry and nomenclature. However, ferrocene is different from phenyl with respect to stereochemistry : a derivative with at least two different substituents in the same ring cannot be superimposed with its mirror image, i.e., it is chiral. The first compound of this type to be prepared was 3,1'-dimethyl-ferrocenecarboxylic acid, in which both enantiomers were obtained by resolution of the racemate with cinchonidine and quinidine ( Fig. 4-1) [2]. Crystals of one enantiomer suitable for X-ray structure analysis could be grown; this result confirmed unequivocally the correlation with the true configuration of the molecule [3].Schlogl has investigated the problem systematically and suggested this isomerism to be an example of planar chirality fl, 41. A simple rule was developed to assign chirality descriptors to homoannular di-or polysubstituted ferrocenes: The observer regards the molecule from the side of the ring to be assigned (called the "upper" ring). The substituents are then analyzed for priority according to the Cahn -Ingold -Prelog (CIP) rules. If the shortest path from the substituent with highest priority to that following in hierarchy is clockwise, the chirality descriptor is (R), otherwise it is (S) [5]. If both rings bear at least two different substituents, the process is started with the ring containing the substituent of highest priority, the molecule is then turned upside down and the second ring subsequently assigned. In order to show clearly that the chirality descriptor belongs to a planar element of chirality, it is often written as (,R) or ($), respectively. Another convention exists, which states that in ferrocene derivatives with both central and planar chirality, the descriptor of the central chirality is written first. Thus, (R, S) should mean that the compound contains an element of central chirality with ( R ) configuration and an element of planar chirality with (S) configuration. This order is used in this book. However, the opposite order of the descriptors was suggested in a recent monograph 174

show abstract

Ferrocene studies. XVIII. Identification and stereochemistry of nine bimolecular Clemmensen reduction products of benzoylferrocene la--d

Cited by 14 publications

References 3 publications

Synthesis and Antiproliferative Effects of [3]Ferrocenophane Transposition Products and Pinacols Obtained from McMurry Cross-Coupling Reactions

Synthesis and Antiproliferative Effects of [3]Ferrocenophane Transposition Products and Pinacols Obtained from McMurry Cross-Coupling Reactions

Dynamic behaviour of 1,n′-disubstituted ferrocenes

Chiral Ferrocene Derivatives. An Introduction

Contact Info

Product

Resources

About