A cobalt catalyzed protocol for the synthesis of substituted β-phenyl isoserine derivatives

Bhatia, Beena; Jain, Sanjay Kumar; De, Anindita; Bagchi, I.; Iqbal, Javed

doi:10.1016/0040-4039(96)01595-x

Cited by 20 publications

(9 citation statements)

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“…Selective ring-opening reactions of oxiranes also provide powerful and efficient routes to a variety of useful compounds including 2,3-epoxyketone (Meth-Cohn et al 1999), aziridinecarboxylate (Thijs et al 1990). isoserine derivatives (Bhatia et al 1999). The crystal structure of the title compound is reported here.…”

Section: S1 Commentmentioning

confidence: 93%

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3-(4-Nitrophenyl)-N-phenyloxirane-2-carboxamide

2009

Acta Cryst E

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Section: S1 Commentmentioning

confidence: 93%

“…For epoxide-containing compounds used as building blocks in synthesis, see: Righi et al (1996); Bhatia et al (1999); Meth-Cohn et al (1999); Thijs et al (1990).…”

Section: Related Literaturementioning

confidence: 99%

3-(4-Nitrophenyl)-N-phenyloxirane-2-carboxamide

2009

Acta Cryst E

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“…Procedure A: 307 mg, 44% yield; white solid; 1 H NMR (600 MHz, CDCl 3 ) δ 7.36–7.26 (m, 5H), 6.14 (d, J = 6.3 Hz, 0.5H), 5.71 (d, J = 6.0 Hz, 0.5H), 4.31 (d, J = 4.7 Hz, 0.5H, trans -isomer), 3.85 (s, 0.5H, cis -isomer), 3.82–3.77 (m, 1H), 3.76 (d, J = 4.8 Hz, 0.5H, trans -isomer), 3.51 (s, 0.5H, cis -isomer), 1.96–1.89 (m, 1H), 1.76–1.72 (m, 1.5H), 1.64–1.60 (m, 1H), 1.49–1.47 (m, 0.5 H), 1.41–1.33 (m, 1.5 H), 1.28–0.99 (m, 4H), 0.49–0.43 (m, 0.5 H); 13 C NMR (151 MHz, CDCl 3 ) δ 165.0, 133.3, 128.4, 128.3, 126.6, 58.1, 56.2, 47.2, 32.7, 32.2, 29.7, 25.3, 24.6, 24.4. Product 3c is a known compound …”

Section: Methodsmentioning

confidence: 99%

“…15 N-Cyclohexyl-3-phenyl-2,3-epoxy-1-propanamide (3c). Procedure A: 307 mg, 44% yield; white solid; 1 H NMR (600 MHz, CDCl 3 ) δ 7.36−7.26 (m, 5H), 6.14 (d, J = 6.3 Hz, 0.5H), 5.71 (d, J = 6.0 Hz, 0.5H), 4.31 (d, J = 4.7 Hz, 0.5H, trans-isomer), 3.85 (s, 0.5H, cisisomer), 3.82−3.77 (m, 1H), 3.76 (d, J = 4.8 Hz, 0.5H, trans-isomer), 3.51 (s, 0.5H, cis-isomer), 1.96−1.89 (m, 1H), 1.76−1.72 (m, 1.5H), 1.64−1.60 (m, 1H), 1.49−1.47 (m, 0.5 H), 1.41−1.33 (m, 1.5 H), 1.28−0.99 (m, 4H), 0.49−0.43 (m, 0.5 H); 13 16 trans-1-(4-Bromophenyl)-2,3-epoxy-5-methyl-1-hexanone (3d). Procedure A: 316 mg, 53% yield; white solid; mp 44−45 °C; 1 H NMR (600 MHz, CDCl 3 ) δ 7.90 (d, J = 8.5 Hz, 2H), 7.64 (d, J = 8.5 Hz, 2H), 3.94 (d, J = 1.7 Hz, 1H), 3.16 (ddd, J = 6.7, 4.9, 1.9 Hz, 1H), 1.95−1.85 (m, 1H), 1.66 (ddd, J = 12.1, 7.3, 4.8 Hz, 1H), 1.61−1.55 (m, 1H), 1.01 (d, J = 6.5 Hz, 3H), 1.00 (d, J = 6.4 Hz, 3H); 13 Product 3j is a known compound.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Darzens Reaction Rate Enhancement Using Aqueous Media Leading to a High Level of Kinetically Controlled Diastereoselective Synthesis of Steroidal Epoxyketones

2014

J. Org. Chem.

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Darzens reactions between halocarbonyls and aldehydes have been carried out in water in the presence of a Li(+)-containing base, a phase-transfer catalyst, and granular polytetrafluoroethylene under mechanical stirring. Reactions using both aromatic and aliphatic aldehydes produced epoxides stereoselectively in good to excellent yields. This is the first time that aliphatic aldehydes with α-H have been used in aqueous Darzens reactions. The Darzens reactions were much faster in water than in organic solvents. This aqueous rate enhancement occurred for Darzens reactions between enantiopure steroidal haloketones and aldehydes, yielding enantiopure spiroepoxides with a high level of kinetically controlled diastereoselectivity. Chromatography was avoided in the purifications of the steroidal spiroepoxides. This is an example of preparing enantiopure epoxyketones via aqueous Darzens reaction using chiral α-haloketone substrates.

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“…2 b-Lactams themselves are important antibiotics and clinically important molecules, 3 so numerous synthetic methods have been developed to construct b-amino acids and b-lactam skeletons. For instance, the Mannich reaction, 4 Michael addition (nitrogen nucleophiles), 5 base-catalyzed ring-opening of b-lactams, 6 epoxide ringopening by nitrogen nucleophiles, 7 aziridine ringopening 8 and Sharpless aminohydroxylation 9 are some of the methods used to synthesize b-amino acids. Despite the impressive range of synthetic methods, newer and simpler methods by which chemists can control the regio-and stereoselectivity of the synthesis of b-amino esters are highly desirable.…”

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confidence: 99%

Synthesis of β-Amino Esters by Regioselective Amination of Allyl Bromides with Aryl and Alkyl Amines

Chen¹,

Patkar²,

Ueng³

et al. 2005

Synlett

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One of the two possible regioisomers can be exclusively formed by combining a suitable solvent and a specific amount of triethylamine as a base during the amination of allyl bromide 5. The S N 2¢ product 7 was produced using dichloromethane as a solvent and triethylamine (7 equiv) as base; S N 2 product 6 was predominantly generated in hexane with 0.5 equivalents of triethylamine. Furthermore, a new reaction condition for the efficient cyclization of 7 to yield a-methylene b-lactam 8 using Sn[N(TMS) 2 ] 2 as a reagent, is disclosed.Key words: b-amino ester, amination, regioselectivity, a-methylene b-lactam, allyl bromide b-Amino acid is a non-proteinogenic amino acid and an important moiety in many biologically active compounds. 1 It is an important precursor in the synthesis of blactams. 2 b-Lactams themselves are important antibiotics and clinically important molecules, 3 so numerous synthetic methods have been developed to construct b-amino acids and b-lactam skeletons. For instance, the Mannich reaction, 4 Michael addition (nitrogen nucleophiles), 5 base-catalyzed ring-opening of b-lactams, 6 epoxide ringopening by nitrogen nucleophiles, 7 aziridine ringopening 8 and Sharpless aminohydroxylation 9 are some of the methods used to synthesize b-amino acids. Despite the impressive range of synthetic methods, newer and simpler methods by which chemists can control the regio-and stereoselectivity of the synthesis of b-amino esters are highly desirable. Scheme 1 presents one such simple method in which a nitrogen nucleophile attacks allyl bromide intermediate 2, obtained from Baylis-Hillman adduct 1, to yield S N 2 b-amino acid 3 and S N 2¢ product 4 (for E = COOR, Scheme 1). 2b However, the nucleophilic attack by nitrogen at the allyl bromide a,b-unsaturated system commonly leads to the formation of a mixture of S N 2 and S N 2¢ products. 2b,10-12 This work reports the regioselective amination of allyl bromo a,b-unsaturated compounds by controlling the solvent and the base.In earlier investigations of the amination of allyl bromides 2 (Scheme 1), where the substituents at the C-2 positions were nitrile, 10 sulfonyl, 11 ketone 12 or ester, 2b,12a,13 the product formation depended on the steric bulk and basicity of the nitrogen nucleophile, on the polarity of the solvent used in the reaction, and on the substituent at C-2 position of the allyl bromide 2. The addition of amine to the allyl bromide 2 with ester substituent at the C-2 position has been reported to yield a mixture of 3 and 4. 2b,12a The thermodynamically more stable product 3 was produced by the S N 2 replacement of the bromide with amine, and the kinetic product 4 was formed by either N-allylic rearrangement or the S N 2¢ replacement of allyl bromide with amine. [10][11][12][13] In this work the polarity of the solvent, the basicity of the nucleophilic amines and amount of base strongly affected the regioselective addition of allylic bromides with arylamines.As shown in Table 1, the reaction time was shortened from four days to under 12 hours, and the...

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A cobalt catalyzed protocol for the synthesis of substituted β-phenyl isoserine derivatives

Cited by 20 publications

References 6 publications

3-(4-Nitrophenyl)-N-phenyloxirane-2-carboxamide

3-(4-Nitrophenyl)-N-phenyloxirane-2-carboxamide

Darzens Reaction Rate Enhancement Using Aqueous Media Leading to a High Level of Kinetically Controlled Diastereoselective Synthesis of Steroidal Epoxyketones

Synthesis of β-Amino Esters by Regioselective Amination of Allyl Bromides with Aryl and Alkyl Amines

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