Amino acids and peptides—XIV

Takamura, Norio; Mizoguchi, Tomishige; Koga, Kenji; Yamada, Shunichi

doi:10.1016/0040-4020(75)85070-8

Cited by 69 publications

(18 citation statements)

References 9 publications

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“…Ethyl diazoacetate, ethyl diazoacetoacetate, (trimethylsilyl)diazomethane (2  hexanes solution), and the chemicals used for the preparation of diazo ketones were purchased from Aldrich Chemical Co. N 2 C(CH 2 CHMe 2 )COOMe has been prepared according to the literature. [19] The diazo ketones were prepared from the corresponding acyl chlorides and diazomethane by the ArndtϪEistert method. [20] Liquid N 2 CHCOR compounds [R ϭ Me (3), Et (4), nPr (5), and iPr (6)] were purified by vacuum distillation.…”

Section: Methodsmentioning

confidence: 99%

Functionalisedcis-Alkenes from the Stereoselective Decomposition of Diazo Compounds, Catalysed by [RuCl(η5-C5H5)(PPh3)2]

Zotto¹,

Baratta²,

Verardo³

et al. 2000

Eur. J. Org. Chem.

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A catalytic amount of [RuCl(η 5 -C 5 H 5 )(PPh 3 ) 2 ] (1) (0.1 mol-%) at 60°C stereoselectively decomposes α-diazo carbonyl compounds N 2 CHCOR [R = EtO, Me, Et, nPr, iPr, Ph, (CH 2 ) 10 Me, and (CH 2 ) 14 Me] affording quantitatively RCOCH=CHCOR carbene dimers [R = EtO (10), Me (11), Et (12), nPr (13), iPr (14), Ph (15), (CH 2 ) 10 Me (16), and (CH 2 ) 14 Me (17)]. The cis isomer is formed in 95−99% purity, depending on the R group. Under the same experimental conditions, N 2 CHCOR 1 and N 2 CHCOR 2 react in equimolar amounts to give mixtures of unsymmetrical cis-R 1 COCH=CHCOR 2 (18−32), and symmetrical cis-R 1 COCH=CHCOR 1 and cis-R 2 COCH=CHCOR 2 alkenes. The unsymmetrical cis-alkenes 23−32 are formed [a]

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Section: Methodsmentioning

confidence: 99%

Functionalisedcis-Alkenes from the Stereoselective Decomposition of Diazo Compounds, Catalysed by [RuCl(η5-C5H5)(PPh3)2]

Zotto¹,

Baratta²,

Verardo³

et al. 2000

Eur. J. Org. Chem.

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“…[19] The diazo ketones were prepared from the corresponding acyl chlorides and diazomethane by the ArndtϪEistert method. Ethyl diazoacetate, ethyl diazoacetoacetate, (trimethylsilyl)diazomethane (2  hexanes solution), and the chemicals used for the preparation of diazo ketones were purchased from Aldrich Chemical Co. N 2 C(CH 2 CHMe 2 )COOMe has been prepared according to the literature.…”

Section: Methodsmentioning

confidence: 99%

Functionalised cis-Alkenes from the Stereoselective Decomposition of Diazo Compounds, Catalysed by [RuCl(η5-C5H5)(PPh3)2]

Del Zotto,

Baratta,

Verardo

et al. 2000

Eur. J. Org. Chem.

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A catalytic amount of [RuCl(η5‐C5H5)(PPh3)2] (1) (0.1 mol‐%) at 60 °C stereoselectively decomposes α‐diazo carbonyl compounds N2CHCOR [R = EtO, Me, Et, nPr, iPr, Ph, (CH2)10Me, and (CH2)14Me] affording quantitatively RCOCH=CHCOR carbene dimers [R = EtO (10), Me (11), Et (12), nPr (13), iPr (14), Ph (15), (CH2)10Me (16), and (CH2)14Me (17)]. The cis isomer is formed in 95−99% purity, depending on the R group. Under the same experimental conditions, N2CHCOR1 and N2CHCOR2 react in equimolar amounts to give mixtures of unsymmetrical cis‐R1COCH=CHCOR2 (18−32), and symmetrical cis‐R1COCH=CHCOR1 and cis‐R2COCH=CHCOR2 alkenes. The unsymmetrical cis‐alkenes 23−32 are formed in about 50% yield from the reaction between two α‐diazo ketones. The yield of the cis‐R1COCH=CHCOR2 compounds 18−22 increases to ca. 60% when a mixture of α‐diazo ketone and N2CHCOOEt is catalytically decomposed. Higher conversions into the unsymmetrical products have been obtained by treating N2CHCOR and N2CHSiMe3, from which cis‐RCOCH=CHSiMe3 derivatives 34−41 are formed in 83−91% yield. The catalytic decomposition of α,ω‐bis(diazo) ketones N2CHCO(CH2)nCOCHN2 (n = 4, 8, or 10) has also been investigated, and found to afford cyclic cis‐alkenes arising from both intra‐ [n = 4 (45), 8 (46), and 10 (47)] and intermolecular carbene‐carbene coupling processes.

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“…Anhydrous CuSOj was obtained from BDH. Starting materials were prepared according to the literature: L-menthyl diazoacetate (4,5), catalyst C (13), catalyst E (141, E-P-thujaketonic acid methyl ester (2 …”

Section: Methodsmentioning

confidence: 99%

“…Conversion of 3 to 4 was achieved by thermal rearrangement of 3 to E-P-thujaketonic acid followed by esterification by CH2N2 It had been shown earlier (2) that selective cyclopropanation of 4 , employing ethyl diazoacetate and copper sulfate, could be achieved with exclusive attack of the generated carbene occurring at the more reactive non-conjugated double bond. To achieve a potential entry into the chiral series, two diazoacetic esters, namely, ethyl diazoacetate and L-menthyl diazoacetate, prepared according to the literature procedure (4,5) were employed along with five different copper catalysts. Two of these catalysts (A, B) were achiral while three continued a chiral ligand (C, D, E) (Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

The chemistry of thujone. XII. The synthesis of pyrethroid analogues via chiral cyclopropanation

Becalski¹,

Cullen²,

Fryzuk³

et al. 1988

Can. J. Chem.

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. Can. J. Chem. 66, 3108 (1988). An extensive study involving achiral and chiral cyclopropanation of various isoprenoid units derived from the monoterpene thujone is presented. Carbenoid intermediates generated from ethyl and L-menthyl diazoacetates and various achiral and chiral copper catalysts are employed to achieve the desired cyclopropanation reaction. It is shown that high levels of enantiomeric excess can be achieved, particularly when L-menthyl diazoacetate and a chiral catalyst are employed. The resultant products are then converted to pyrethroid-like analogues.

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Amino acids and peptides—XIV

Cited by 69 publications

References 9 publications

Functionalisedcis-Alkenes from the Stereoselective Decomposition of Diazo Compounds, Catalysed by [RuCl(η5-C5H5)(PPh3)2]

Functionalisedcis-Alkenes from the Stereoselective Decomposition of Diazo Compounds, Catalysed by [RuCl(η5-C5H5)(PPh3)2]

Functionalised cis-Alkenes from the Stereoselective Decomposition of Diazo Compounds, Catalysed by [RuCl(η5-C5H5)(PPh3)2]

The chemistry of thujone. XII. The synthesis of pyrethroid analogues via chiral cyclopropanation

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