Bis(trifluormethyl)-substituierte azomethin-ylide durch thermolyse von 3-aryl-2,2-bis(trifluormethyl)-1,3-oxa-zolidin-5-onen

Burger, Klaus; Meffert, A.; Bauer, Susanne E.

doi:10.1016/s0022-1139(00)81628-0

Cited by 24 publications

(7 citation statements)

References 8 publications

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“…irradiation of 3a-H caused enhancement of 4-H (3), 11 b-H ( 6), both ArCH, (6), and CH, (3); irradiation of lla-H caused enhancement of 11 b-H ( 7) and CH, (5); m/z (%) 360 ( M + , 15), 255 (loo), and 104 (12).…”

Section: C-vclic Secondary %-Amino Acids With a Benzylic Carboxymentioning

confidence: 96%

“…(1 H, m, lla-H), 2.99 (3 H,s,3.16 (1 H,dd,J 11 and 15 Hz,3.13 (1 H,d,J 14 Hz,3.17 3) and 1 la-H (4); irradiation of 1 la-H caused enhancement of 4-H (4) and llb-H (1); m/z (%) 377 ( M + , 67), 266 (15), 104 (84), and 28 (100). 1,2,3,3a,4,8,8a,8 b-Octahydro-2-methyl-4-(2-phenylethenyl)pyrrolo [3',4': 3,4lpyrrolo[ 1,2-c]thiazole-1,3-dione (15a)-(18a).-A mixture of thiazolidine-4-carboxylic acid (3.0 g, 0.023 mol), trans-cinnamaldehyde (2.97 g, 0.023 mol), and Nmethylmaleimide (2.5 g, 0.023 mol) in dry acetonitrile (50 ml) was stirred and boiled under reflux under a nitrogen atmosphere for 18 h. Unchanged thiazolidinecarboxylic acid (280 mg) was filtered off from the cooled reaction mixture and the filtrate was evaporated under reduced pressure.…”

Section: C-vclic Secondary %-Amino Acids With a Benzylic Carboxymentioning

confidence: 99%

“…CI5Hl,N,O2 requires 256.12117; v, , , . 1 760, 1 690, and 710 cm-'; 6 1.92 (1 H, m, 7p-H), 2.67 (1 H, m, 7a-H), 3.02 (1 H, dd, J 9 and 18 Hz, 6P-H), 3.05 (3 H,s,NMe),3.55 (1 H,dd,J 1.4 and 9 Hz,3.61 (1 H, t, J 9 Hz,3.67 (1 H,m,4.52 (1 H,m,4.57 (1 H,br s,m,ArH); 'H NOEDSY (x): irradiation of 3a-H caused enhancement of 4-H (2); irradiation of 6x-H caused enhancement of 60-H ( 18), 7a-H (3), and ArH (0.5); irradiation of 7a-H caused enhancement of 6a-H (3), 7p-* 2,3,3a,4,6,7,7a,7b-Octahydro-1 H-pyrrolo[3',4' : 3,4]pyrrolo[ 1,2-a H (17), and 7a-H (3); irradiation of 7b-H caused enhancement of 7a-H (6) and ArH (2.3); m / z (%) 256 (M', 32), 165 (loo), and 145 (15).…”

Section: 33aa4p677aa7ba-octahydro-2-methyl-4-phenyl-1 Hpyrrolo[3'4' :...mentioning

confidence: 99%

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XY–ZH systems as potential 1,3-dipoles. Part 12. Mechanism of formation of azomethine ylides via the decarboxylative route from α-amino acids

Grigg¹,

Idle²,

McMeekin³

et al. 1988

J. Chem. Soc., Perkin Trans. 1

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The effect of temperature, solvent, and type of aldehyde on the stereospecific or stereoselective formation of azomethine ylides by the decarboxylative condensation of aldehydes with three types of aamino acids, (i) cyclic secondary a-amino acids, (ii) cyclic secondary a-amino acids with a benzylic carboxy group, and (iii) acyclic primary a-amino acids, has been studied. Stereospecific anti-dipole formation in (i) and temperature dependent stereoselective anti-dipole formation in (ii) and (iii) is inferred from the stereochemistry of cycloadducts of the azomethine ylides with N-methylmaleimide. These results are used to support a mechanistic scheme involving loss of carbon dioxide from in termed iate oxazol id i n -5 -ones in a stereospecif ic cycloreversion react ion. * This conclusion assumes the two dipoles react with N-methylmaleimide faster than they interconvert. Our previous studies 1,9 support this view but with less active dipolarophiles a different situation might obtain. C02 H Ar Ar ( 2 0 ) H H----H OAN AO Me Me (21) a ; A r = Ph ( 2 2 ) b ; A r = 2pyridyl H H H * The results of M.N.D.O. and STO-3G calculations on (34a)-(37a) and other aspects of dipole formation are being prepared for publication (R. Grigg, J. Idle, and P. McMeekin, unpublished observations).

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Section: C-vclic Secondary %-Amino Acids With a Benzylic Carboxymentioning

confidence: 96%

Section: C-vclic Secondary %-Amino Acids With a Benzylic Carboxymentioning

confidence: 99%

Section: 33aa4p677aa7ba-octahydro-2-methyl-4-phenyl-1 Hpyrrolo[3'4' :...mentioning

confidence: 99%

See 1 more Smart Citation

XY–ZH systems as potential 1,3-dipoles. Part 12. Mechanism of formation of azomethine ylides via the decarboxylative route from α-amino acids

Grigg¹,

Idle²,

McMeekin³

et al. 1988

J. Chem. Soc., Perkin Trans. 1

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“…There are also some reports, describing the generation of nonstabilized azomethines by thermolysis of oxazolidinones. [62][63][64][65][66] It is apparent from the many recent contributions in the area that nonstabilized ylides, and particularly the nonstabilized 1,3-dipoles such as azomethine ylides, continue to be of great interest both mechanistically and synthetically. As a means of controllably generating such transient species for either synthetic exploitation or careful study of properties and reactivity, the nucleophilic desilylation of (trimethylsily1)methyl onium salts offers a powerful tool.…”

Section: Cat Csfmentioning

confidence: 99%

Ylides by the desilylation of .alpha.-silyl onium salts

Vedejs¹,

West²

1986

Chem. Rev.

158

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“…Several trifluoromethylpyrrolidines have already been synthesized in the literature, mostly in their racemic forms. Since the first example of pyrrolidine synthesis published by Burger et al, the [3 + 2] cycloaddition of an azomethine ylide and a dipolarophile has often been used to reach β-substituted , or α-substituted , trifluoromethylpyrrolidines. Highly functionalized trifluoromethylpyrrolidines can also be synthesized from a Michael-type addition/annulation sequence on a CF 3 -substituted vinylsulfonium salt, intramolecular cyclization of fluorinated homoallylamines, and one-pot intramolecular cyclization of aminoalkynes followed by nucleophilic addition of the Ruppert reagent .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Enantiopure trans-2,5-Disubstituted Trifluoromethylpyrrolidines and (2S,5R)-5-Trifluoromethylproline

et al. 2015

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Enantiopure trans-2,5-disubstituted trifluoromethylpyrrolidines were prepared on a several gram scale starting from a readily available chiral fluorinated oxazolidine (Fox). A pure oxazolopyrrolidine intermediate could be obtained after an efficient separation by selective diastereomer destruction. The addition of various Grignard reagents on this oxazolopyrrolidine provided disubstituted pyrrolidines with moderate to complete trans diastereoselectivity. The highly valuable compound (2S,5R)-5-trifluoromethylproline could be synthesized from the same oxazolopyrrolidine intermediate via a Strecker-type reaction.

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Bis(trifluormethyl)-substituierte azomethin-ylide durch thermolyse von 3-aryl-2,2-bis(trifluormethyl)-1,3-oxa-zolidin-5-onen

Cited by 24 publications

References 8 publications

XY–ZH systems as potential 1,3-dipoles. Part 12. Mechanism of formation of azomethine ylides via the decarboxylative route from α-amino acids

XY–ZH systems as potential 1,3-dipoles. Part 12. Mechanism of formation of azomethine ylides via the decarboxylative route from α-amino acids

Ylides by the desilylation of .alpha.-silyl onium salts

Synthesis of Enantiopure trans-2,5-Disubstituted Trifluoromethylpyrrolidines and (2S,5R)-5-Trifluoromethylproline

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