Novel Cobalt-Catalyzed Carbonylation of 2-Aryl-2-oxazolines

Xu, Hongfei; Li, Jia

doi:10.1021/ol034380f

Cited by 37 publications

(12 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This substrate suffered from lower activity, and required 10 mol % catalyst to achieve only 50 % conversion 27. This reduced reactivity, also observed by Jia,15a is likely due to the sterics at the 5‐position, as the isomeric 4‐methyl derivative was cleanly carbonylated in high conversion using only 1 mol % catalyst (Table 2, entry 1). Despite the lower conversion to oxazinone for this substrate, we examined the carbonylation of the 5 R ‐methyl derivative, ( R )‐ 2 h , with 10 mol % catalyst.…”

Section: Methodssupporting

confidence: 52%

Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids

et al. 2008

View full text Add to dashboard Cite

show abstract

Section: Methodssupporting

confidence: 52%

Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids

et al. 2008

View full text Add to dashboard Cite

show abstract

“…We reported in 2001 the first example of metal-catalyzed carbonylative polymerization of aziridine under the hypothesis that aziridine enchainment would occur via sequential nucleophilic reactions as shown in Scheme 1 [46]. In the past several years, we investigated the heteroatom-containing substrates including N-alkylaziridnes, 2-oxazolines, epoxides, N-alkylazetidines, and THF [47][48][49][50][51][52]. DarensbourgÕs group directly investigated the kinetics and mechanism of the N-alkylaziridine carbonylative polymerization in a joint effort with us [53].…”

Section: Introductionmentioning

confidence: 99%

The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

LeGall

et al. 2005

Journal of Organometallic Chemistry

Self Cite

View full text Add to dashboard Cite

“…The carbonylation of alkyl or aryl halides such as benzyl halides easily proceeds using the cobaltcarbonyl catalysts. 60 -65,341 -351 The other carbonylations are also reported on exocylic carbonylations of cycloimino esters, 352 ring-expanding carbonylations of 2-aryl-3-oxazolines, 353 active epoxide carbonylations to β-lactones 354 or polyesters, 355 carboylative silycarbocyclization of 1,6-enynes, 356 hydromethoxycarbonylation of 1,3-butadiene, etc. 357…”

Section: Materials Nanoscience and Catalysismentioning

confidence: 99%

“…352 Catalytic ring-expanding carbonylations of 2-aryl-2oxazolines proceed by carbonylation with PhCH 2 -Co(CO) 4 under 200 psi of CO pressure, as shown in equation (48). 353 The reaction is considered to proceed via carbonyl insertion to the cobalt-carbon bond and reductive elimination of cobalt catalyst.…”

Section: Other Carbonylationsmentioning

confidence: 99%

Three characteristic reactions of organocobalt compounds in organic synthesis

Omae

2007

Applied Organom Chemis

View full text Add to dashboard Cite

Organocobalt compounds in organic synthesis have three characteristic reactions. The first occurs because cobalt has a high affinity to carbon-carbon π -bonds or carbon-nitrogen π -bonds. The second occurs because cobalt has a high affinity to carbonyl groups. The third is due to cobalt easily tending to form square-planar bipyramidal six-coordination structures with four nitrogen atoms or two nitrogen atoms and two oxygen atoms at the square-planar position, and to bond with one or two carbon atoms at the axial position. The first characteristic reactions are the representative reactions of organocobalt compounds with a mutually bridged bond between the two π -bonds of acetylene and the cobalt-cobalt bond of hexacarbonyldicobalt. These are reactions with a Co 2 (CO) 6 INTRODUCTIONOrganometallic intramolecular coordination compounds, especially five-membered ring compounds of organotin compounds, have been studied since 1965, and many reviews 1 -13 and some books 14 -16 have published on the subject. These compounds are mainly synthesized by cyclometalation reactions with transition metal compounds. The first publication on this subject is generally considered to be the reaction of diazobenzene with nick elocene by Kleiman and Dubeck 17 in 1963 as shown in equation (1).*Correspondence to: Iwao Omae, Nihon Pharmaceutical University, 10281, Komuro, Ina-cho, Saitama, An earlier article on the direct synthesis of 2-phenyl-3-indazolinone by carbonylation of azobenzene with a cobalt Materials, Nanoscience and CatalysisThree characteristic reactions of organocobalt compounds 319 carbonyl catalyst, as shown in equation (2), was published in 1956. 18 It was also synthesized in 1967 through a twostep reaction, that is, (i) cyclopalladation of azobenzene via the five-membered ring product, and (ii) carbonylation, as shown in equation (3). 19From these two reactions, the former reaction [equation (2)] is presumed also to proceed via cyclometallation, that is, cyclocobaltation with the cobalt carbonyl catalyst, as shown in equation (4). Actually, many cyclomatalations with cobalt compounds have been reported. 20 -35 For example, a similar cyclometalated organocobalt compound was prepared by the reaction of azobenzene with methyltetra(trimethylphosphine)cobalt, as shown in equation (5). 20 Further, one year previously, in 1955, the same type of heterocyclic compound was prepared by the same type of carbonylation reaction with an organocobalt compound, as shown in equation (6). 36 This publication by Murahashi 36 may be considered to be the first reaction relating cyclometalation reactions.In the chemical industry, organocobalt is an essential constituent in many important catalysts. Specifically, they are key components in the multimillion-pound technology of hydroformylation; that is, the catalytic transformation of olefins into aldehydes using homogeneous catalysts. This article reports on three characteristic reactions of the organocobalt compounds in organic syntheses on the basis of their structures and reactivities...

show abstract

Novel Cobalt-Catalyzed Carbonylation of 2-Aryl-2-oxazolines

Abstract: Catalytic ring-expanding carbonylation of 2-aryl-2-oxazolines is reported as a novel method for the synthesis of 4,5-dihydro-1,3-oxazin-6-ones. Various observations suggest the involvement of cobalt radicals as the catalytically active species. [reaction: see text]

Cited by 37 publications

References 26 publications

Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids

Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids

The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

Three characteristic reactions of organocobalt compounds in organic synthesis

Contact Info

Product

Resources

About

Novel Cobalt-Catalyzed Carbonylation of 2-Aryl-2-oxazolines

Abstract: Catalytic ring-expanding carbonylation of 2-aryl-2-oxazolines is reported as a novel method for the synthesis of 4,5-dihydro-1,3-oxazin-6-ones. Various observations suggest the involvement of cobalt radicals as the catalytically active species. [reaction: see text]

Cited by 37 publications

References 26 publications

Catalytic Synthesis of β3‐Amino Acid Derivatives from α‐Amino Acids

Catalytic Synthesis of β3‐Amino Acid Derivatives from α‐Amino Acids

The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

Three characteristic reactions of organocobalt compounds in organic synthesis

Contact Info

Product

Resources

About

Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids

Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids