To access a cheminform abstract of an article which was published elsewhere, please select a full text option. Novel arene chromium carbonyl complexed mustard agents have been prepared. Phil new college trinity 1989 oxford abstract this thesis describes the application of arene crco3 methodology to the stereoselective and enantioselective synthesis of substituted arenes. However, the following two methods are the most commonly employed ones. The optically pure tricarbonyl h62substituted benzaldehydes chromium are used as chiral auxiliaries in the condensation with a series of doubly lithiated carboxylic acids. The aqueous layers from the chromium mediated reactions and any other waste materials should be disposed of properly. The complexation of an arene to a chromium tricarbonyl unit changes its. The two intermediates selected were piacetophenone chromium tricarbonyl and pibenzyl bromide chromium tricarbonyl.
This yellow crystalline solid compound is soluble in common. Journal of the chemical society, perkin transactions 1 regioselective nucleophilic additions to tricarbonyl. Tricarbonylcycloheptatriene chromium0 98% cas number 12125723. Molecules free fulltext tricarbonylh6arenechromium0. Arene chromium tricarbonyl chemistry, cheminform on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. It was envisaged that the addition of an organometallic reagent to the carbonyl group within orthosubstituted aryl aldehydechromium tricarbonyl complex 4 may be a selective alternative procedure to create a benzylic stereogenic centre, and that reduction of the corresponding orthosubstituted aryl ketonechromium tricarbonyl complexes 7 r.
Chromium arene complexes in organic synthesis semantic scholar. Download a prospectus postgraduate research admissions postgraduate research fees for postgraduate research. Tricarbonylmesitylene chromium0 98% cas number 12129678. The complexation of a crco unit to an aromatic hydrocarbon enhances the benzylic position towerds attack by base and the resulting carbanion reacts with carbonyl compounds to produce a complexed alcohol. Chromium arene complexes in organic synthesis marta rosillo, gema dom. The structures of nine crystalline complexes were determined by xray. Epimeric pyrroloimidazolone auxiliaries in the diastereoselective synthesis of chiral nferrocenylnphenyl ligands and arene chromium tricarbonyl complexes by cody wilsonkonderka, b. Nonracemic derivatives of a tricarbonyl eta6 arene chromium complex derived from 1,3dihydroisobenzofuran are also prepared in up to 99% ee by chiral base deprotonation, and trends in the. The resulted isoxazolidines were produced with a full regioselectivity and high. Benzene chromium 0 tricarbonyl is one of numerous organometallic compounds also known as metalorganic, organoinorganic and metalloorganic compounds sold by american elements under the trade name ae organometallics for uses requiring nonaqueous solubility such as recent solar energy and water treatment applications. The intramolecular ring closure of the obtained crco3 complexed.
Both styrene and ethynylbenzene complexes react with alkynes and olefins. Asymmetric synthesis of secondary benzylic alcohols via arene. Heckreaction planar chirality arene complex chromium. Mathews department of chemistry, clemson university, clemson, so, 29634 usa abstract. Secondly, we are interested in the 2methylanisole chromium tricarbonyl complex, which has an electron withdrawing oxygen attached to the arene ring which should pull electron density from the metal, leaving less to backbond with the carbonyl ligands, resulting in a. A thesis submitted in partial fulfillment of the requirements for the degree of master of science in chemistry.
Reactions that focus on nucleophilic additions to the chromium. Benzene chromium tricarbonyl is an organometallic compound with the formula crc 6 h 6co 3. The synthesis of enynes connected through chromiumcomplexed aromatic rings is developed. Thiation of arene tricarbonyl chromium 0 complexes. Benzylic activation and stereocontrol in tricarbonylarene. Stereoselective bisfunctionalizations of arene chromium. The first rr arene chromium tricarbonyl compound was synthesized by fischer and ofele in 1957.
Molecules free fulltext tricarbonylh6arenechromium. Download ris reference manager download bib bibtex back to article. Benzylic activation and stereochemical control in reactions. Wells, darrell keith, arene tricarbonyl complexes of chromium 0, molybdenum 0, and tungsten 0 1969. Tricarbonylcycloheptatrienechromium0 98% sigmaaldrich. The structures of nine crystalline complexes were determined by xray diffraction. Photolysis of arene chromium tricarbonyl complexes in.
Intramolecular pd catalyzed carbocyclization reactions. Initial nucleophilic addition of organolithium reagents to a carbonyl moiety is followed by a 1,4carbon to oxygen silyl migration brook rearrangement and alkylation of the resultant aryl anion. Tricarbonyl arene chromium complexes are susceptible to oxidation in solution and should be handled in an. In each case, the nucleophiles would then be expected to approach complexes 5 and 8 anti to the bulky chromium tricarbonyl moiety, giving rise to the epimeric adducts 6 and 9, respectively. The molecule adopts a geometry known as piano stool because of the planar arrangement of the aryl group and the presence of three co ligands as legs on the chromium bond axis.
Abstract orthobutenylchlorobenzene tricarbonylchromium complexes undergo intramolecular pd catalyzed cyclizations heckreactions without decomplexation andor alkene isomerization. In the latter case the ketyl radical adds directly to the complexed arene. By working in flow mode, it is possible to avoid some of the problems of batch synthesis, especially sublimation of the crco 6 starting material and the competitive decomposition of the product during the lengthy reaction times. Download ris reference manager download bib bibtex cited references. Khand reaction occurs in a totally diastereoselective manner. Benzylic activation and stereocontrol in tricarbonyl. Similar results can sometimes also be achieved with nanoparticles.
Preparation of arene chromium tricarbonyl complexes using continuousflow processing. Arene tricarbonyl complexes of chromium 0, molybdenum 0. Jun 15, 2011 read photolysis of arene chromium tricarbonyl complexes in presence of amineboranes. Chromium arene complexes in organic synthesis chemical society. Treatment of the chiral complex 1 with smi 2 gives tricycle 2 selectively by a 5. Contact us postgraduate research postgraduate certificates and diplomas. Aryl aldehyde and aryl ketone chromium tricarbonyl complexes orthosubstituted with the chiral auxiliary omethyln. It is involved in the hydrogenation of 1,3conjugated dienes and oxidation of allylic and benzylic positions.
Benzenechromium tricarbonyl is an organometallic compound with the formula crc 6 h 6co 3. In 1957, fischer and ofele published the preparation of tricarbonyl. Subsequent experimentation revealed that, in most cases, rrchromiu. Chromium arene complexes in organic synthesis marta rosillo, gema domnguez and javier pe. The molecule adopts a geometry known as piano stool because of the planar arrangement of the aryl group and the presence of three co ligands as legs on the. The genet thon of new c2symmetric ethers with high enantioselectivity is demonstrated. Romp and rcm zieglernatta catalyst zieglernatta catalysts are used to polymerize.
Intramolecular pd catalyzed carbocyclization reactions with planar chiral arene tricarbonyl chromium complexes. Stereoselective reactions of arene chromium tricarbonyl complexes. Hexacarbonylchromium is widely used as a catalyst for isomerization of alkenes. Photolysis of arene chromium tricarbonyl complexes. Asymmetric synthesis of secondary benzylic alcohols via. The two intermediates selected were piacetophenone chromium tricarbonyl and pibenzyl bromide chromium. Arene tricarbonyl complexes of chromium 0, molybdenum. In these reactions the influence of electrondonating and electronaccepting substituents in the tricarbonyl arene chromium system is weak. This yellow crystalline solid compound is soluble in common nonpolar organic solvents. The fourth chapter is a study of arene chromium tricarbonyl complexes of dibenzyl ethcl and a dibclizy laminc, dnd their as mmetr ie dept otonatioll. Grubbs catalyst a catalyst for olefin metathesis reactions olefin metathesis reaction.
The synthesis of enynes connected through chromium complexed aromatic rings is developed. A continuousflow approach to the direct synthesis of arene chromium tricarbonyl complexes is presented. Arene exchange reactions of arenetricarbonylchromium complexes. These intermediates would be particularly wellsuited for the preparation of monocomplexed diaryl compounds. Scission and regeneration of carboncarbon bonds some important classes of olefin metathesis reactions are. In this article, catalytic activities of these complexes in hydrogenation and isomerization are discussed. The original article is trackable via the references option. Cheminform is a weekly abstracting service, delivering concise information at a glance that was extracted from about 100 leading journals. Influence of substituents in tricarbonyl arene chromium. Regioselective nucleophilic additions to tricarbonyl. This project was concerned wit hthe preparation of two pi arene chromium tricarbonyl compounds that could serve as a synthetic intermediates to more complex systems.
Compounds of chromium are toxic and must be used in a wellventilated fume hood. Preparation of arene chromium tricarbonyl complexes using. Proposed strategy to create benzylic stereogenic centres. Tricarbonyl mesitylene chromium 0 98% cas number 12129678. Tricarbonyl arene chromium complexes are susceptible to oxidation in solution and should be handled in an inert atmosphere. Brought to you by the organic reactions wiki, the online collection of organic reactions. Initial nucleophilic addition of organolithium reagents to a carbonyl moiety is followed by a 1,4carbon to oxygen silyl migration brook rearrangement and alkylation of. Sorry, we are unable to provide the full text but you may find it at the following locations. A thesis submitted in partial fulfillment of the requirements. These compounds may be easily decomplexed and deprotected to give the. Benzenechromium tricarbonyl is an organometallic compound with the formula crc6h6co3. Asymmetric synthesis of secondary benzylic alcohols via arene chromium tricarbonyl complexes aryl aldehyde and aryl ketone chromium tricarbonyl complexes orthosubstituted with the chiral auxiliary omethyln.
The cr atom is bound to the pyridine ring via the 7relectron system and is situated directly below the heteroarene ring centre. As a result, these reactions of chromium arene complexes are often faster than analogous reactions of free arenes. The second chapter looks at the synthesis of a novel benzyl phosphine chromium tricarbonyl complex and attempts to asymmetrically deprotonate the molecule in. Synthesis and selected reactions of piarene chromium. Regioselective addition of tbutyllithium to tricarbonyl. An efficient method has been developed for the stereoselective bisfunctionalization of arene chromium tricarbonyl complexes. Benzene chromium0 tricarbonyl is one of numerous organometallic compounds also known as metalorganic, organoinorganic and metalloorganic compounds sold by american elements under the trade name ae organometallics for uses requiring nonaqueous solubility such as recent solar energy and water treatment applications. Read photolysis of arene chromium tricarbonyl complexes in presence of amineboranes. Arene tricarbonyl complexes of chromium o, molybdenumo, md tungsteno by darrell keith wells a dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of doctor of philosophy major subject.
Benzylic functionalization of arenetricarbonylchromium. Arene tricarbonyl complexes of chromium 0, molybdenum 0, and tungsten 0 darrell keith wells iowa state university follow this and additional works at. Pdf download buy article permissions and reprints all articles of this category arene chromium tricarbonyl complexes have been widely used in synthetic organic chemistry. The 1,3dipolar cycloaddition products of c,ndisubstituted nitrones and different in situ prepared mononsubstituted nitrones to. The complexation of an arene to a chromium tricarbonyl unit changes its chemical behavior, giving rise. The unusual features include a large upfield shift of alkene proton chemical shifts on complex formation, but within the metals the order. Nuclear magnetic resonance study of arene metal tricarbonyl. The molecular structure of tricarbonyl rl6pyridine chromium 0, crco3c5h5n, is presented here. Citeseerx document details isaac councill, lee giles, pradeep teregowda.
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