Reactions of lithio trimethylsilyl compounds with nitrones

Tsuge, Otohiko; Sone, Kazunori; Urano, Satoshi; Matsuda, Koyo

doi:10.1021/jo00147a026

Cited by 29 publications

(7 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Triphenylphosphine, cinnamic acid, phenol, 4-methoxyphenol, 4-nitrophenol, and p -cresol were purchased from Merck and 4-methoxycinnamic acid, 4-methylcinnamic acid, and 4-nitrocinnamic acid from Aldrich; all were used without further purification. Pt(PPh 3 ) 3 , Pt(PPh 3 ) 2 C 2 H 4 , the acid chlorides, and the alkyl cinnamates were synthesized according to literature procedures. ,− …”

Section: Methodsmentioning

confidence: 99%

Influence of Electronically and Sterically Tunable Cinnamate Ligands on the Spectroscopic Properties and Reactivity of Bis(triphenylphosphine)platinum(0) Olefin Complexes

et al. 2013

View full text Add to dashboard Cite

A total of 48 new bis(triphenylphosphine)(cinnamic acid ester)platinum(0) complexes were synthesized to examine electronic and steric influences on their behavior as inhibited precatalysts and to correlate this with 1 H, 13 C, 19 F, 31 P and 195 Pt NMR spectroscopic, IR spectroscopic, and X-ray structural properties (9 X-ray structures included). The substituent at the 4-position of the phenyl group proved to be a valuable moiety in controlling the electronic properties of the olefin ligand and, therefore, the metal−ligand bond strength. Reactivity and NMR spectroscopic data correlate with the Hammett parameters of this substituent: in particular, the coupling constants 2 J PP and 1 J PPt . The reactivity of the complexes was determined via NMR titration with triphenylphosphine ( 1 H NMR; triggering ligand substitution) and reaction with diphenylsilane ( 1 H and 29 Si NMR; triggering oxidative addition). The determined equilibria correlate with the electron density of the olefin. As one quintessence the reactivity can be predicted indirectly from the NMR 2 J PP coupling constants of the complexes, as was also found for the related Pd complexes.

show abstract

Section: Methodsmentioning

confidence: 99%

Influence of Electronically and Sterically Tunable Cinnamate Ligands on the Spectroscopic Properties and Reactivity of Bis(triphenylphosphine)platinum(0) Olefin Complexes

et al. 2013

View full text Add to dashboard Cite

show abstract

“…In some cases, the formation of 2,3-dihydro-1H-pyrroles has been observed. For example, thermolysis of 1-methyl-2-(4-methylphenyl)-3-(2-pyridyl)aziridine and 11 was reported to yield a compound of this type [17]. Furthermore, photolysis of trans-1-butyl-2,3-diphenylaziridine and 11 afforded a mixture of all three types of 1H-pyrrole derivatives [18].…”

Section: Methodsmentioning

confidence: 99%

New Studies on [2+3] Cycloadditions of Thermally Generated N‐Isopropyl‐ and N‐(4‐Methoxyphenyl)‐Substituted Azomethine Ylides

Urbaniak

Szymański

Romański

et al. 2004

Helvetica Chimica Acta

View full text Add to dashboard Cite

The thermal reaction of 1-substituted 2,3-diphenylaziridines 2 with thiobenzophenone (6a) and 9H-fluorene-9-thione (6b) led to the corresponding 1,3-thiazolidines (Scheme 2). Whereas the cis-disubstituted aziridines and 6a yielded only trans-2,4,5,5-tetraphenyl-1,3-thiazolidines of type 7, the analogous reaction with 6b gave a mixture of trans-and cis-2,4-diphenyl-1,3-thiazolidines 7 and 8. During chromatography on SiO 2 , the trans-configured spiro[9H-fluorene-9,5'-[1,3]thiazolidines] 7c and 7d isomerized to the cis-isomers. The substituent at N(1) of the aziridine influences the reaction rate significantly, i.e., the more sterically demanding the substituent the slower the reaction. The reaction of cis-2,3-diphenylaziridines 2 with dimethyl azodicarboxylate (9) and dimethyl acetylenedicarboxylate (11) gave the trans-cycloadducts 10 and 12, respectively (Schemes 3 and 4). In the latter case, a partial dehydrogenation led to the corresponding pyrroles. Two stereoisomeric cycloadducts, 15 and 16, with a trans-relationship of the Ph groups were obtained from the reaction with dimethyl fumarate (14; Scheme 5); with dimethyl maleate (17), the expected cycloadduct 18 together with the 2,3-dihydropyrrole 19 was obtained (Scheme 6). The structures of the cycloadducts 7b, 8a, 15b, and 16b were established by X-ray crystallography.

show abstract

“…20,28 22,29 24,30 27,31 2832 and 2929 have been previously reported in the literature. H NMR (400 MHz, CDCl 3 ): d = 7.13-7.29 (m, 7 H), 6.82 (d, J = 8.8 Hz, 2 H), 4.51 (t, J = 8.0 Hz, 1 H), 3.76 (s, 3 H), 3.58 (s, 3 H), 3.03 (d, J = 7.6 Hz, 2 H).…”

mentioning

confidence: 86%

Rhodium-Catalyzed Heck-Type Coupling of Boronic Acids with Activated Alkenes in an Aqueous Emulsion

Lautens¹,

Mancuso²,

Grover³

2004

Synthesis

View full text Add to dashboard Cite

Intermolecular couplings between arylboronic acids and activated alkenes catalyzed by a water-soluble tert-butyl amphosrhodium complex were found to progress at room temperature and generated Heck-type products with high yields and excellent selectivity. Substitution on the alkene component encouraged the formation of products arising from a conjugate addition-protonation process. In the case of Heck product formation, it was necessary to add two equivalents of the alkene component whereby one equivalent is believed to act as a sacrificial hydride acceptor.Transition-metal catalysis enjoys widespread use as a method for the creation of carbon-carbon bonds with high efficiency and often negligible byproduct formation. 2 Palladium is usually the metal of choice for s-bond formation as evidenced by the numerous coupling protocols in current use. 3 Cross-couplings using rhodium catalysts have also been examined in search of protocols which could display novel reactivity or selectivity. Rh-catalyzed arylation of olefins has been achieved with Ar-M species where M = B, Si, and Sn in particular. 4,5 Our recent studies determined that cross-coupling between arylboronic acids and styrene-type olefins or 2-vinyl(azaheteroaromatics) could occur in neat water using SDS as a surfactant with a Rh(I) catalyst. 6 A bis(sulfonated) analogue of triphenylphosphine, TPPDS, was used to solubilize the catalyst in the aqueous phase. Although the presence of water is required to generate a catalyticallyactive Rh(I)-OH intermediate, 7 a competing protodemetalation pathway was active, resulting in diminished yields of product if boronic acid loading was low. The use of SDS was beneficial in ameliorating chemical yields, but organic co-solvents proved ineffective.We recently reported a rhodium-catalyzed cascade-type reaction in which an arylboronate ester bearing a pendant Michael acceptor olefin (1) could cyclize onto strained olefins with high diastereoselectivity (Scheme 1). 8 The reaction took place within an organic/aqueous emulsion employing SDS as phase transfer reagent. A salient feature of this process was that bulky, electron rich, water-soluble phosphines, such as the amphos class of ligands 9 (Figure 1), were required to obtain high yields.It was of interest to determine if we could replace the strained olefin coupling partner with other classes of olefin to extend the reaction scope. Substrate 1 was tested with a variety of activated alkenes, including Nakamura's protected cyclopropenone, 10 maleic anhydride, hydroquinone, and 3-sulfolene but these did not generate any desired cross-coupled products. Scheme 1 Rh(I)-catalyzed cascade-type reaction between bifunctional arylboronate esters and strained olefinsFigure 1 Bulky, electron-rich, water-soluble phosphine ligandsHowever, as shown in Scheme 2, tert-butyl acrylate gave a product arising from a Heck-type addition. The newly created double bond in 2 was formed selectively as the trans isomer. Cyclopentenone gave product 3 arising from a conjugate addition-protonation process....

show abstract

Reactions of lithio trimethylsilyl compounds with nitrones

Abstract: distilled in a Kugelrohr apparatus at 140-145 °C (0.02 torr) to afford GLC-pure product (6.85 g) as a yellow liquid: 38% yield as 7;

Cited by 29 publications

References 4 publications

Influence of Electronically and Sterically Tunable Cinnamate Ligands on the Spectroscopic Properties and Reactivity of Bis(triphenylphosphine)platinum(0) Olefin Complexes

Influence of Electronically and Sterically Tunable Cinnamate Ligands on the Spectroscopic Properties and Reactivity of Bis(triphenylphosphine)platinum(0) Olefin Complexes

New Studies on [2+3] Cycloadditions of Thermally Generated N‐Isopropyl‐ and N‐(4‐Methoxyphenyl)‐Substituted Azomethine Ylides

Rhodium-Catalyzed Heck-Type Coupling of Boronic Acids with Activated Alkenes in an Aqueous Emulsion

Contact Info

Product

Resources

About