Regioselective ring opening of chiral epoxyalcohols by primary amines

Canas, M.; Poch, Marta Peguera; Verdaguer, Xavier; Moyano, Albert; Pericàs, Miquel À.; Riéra, Antoni

doi:10.1016/0040-4039(91)80447-e

Cited by 78 publications

(21 citation statements)

References 10 publications

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“…We then focused on the regio-and stereoselective Ti(Oi-Pr) 4 -catalysed ringopening process developed by Pericàs and Riera. 8 When treated with benzylamine under these conditions, 2,3-epoxyalcohol 10 afforded the expected aminodiols 11 and 12 in 75% yield and in a 70:30 ratio, in favour of C-3 opening. The two regioisomers were separated for full characterisation.…”

Section: Preparation Of the 4-oxazolidinonecarbaldehyde Intermediatementioning

confidence: 97%

Enantioselective access to a versatile 4-oxazolidinonecarbaldehyde and application to the synthesis of a cytotoxic jaspine B truncated analogue

Génisson

Lamandé

Salma

et al. 2007

Tetrahedron: Asymmetry

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Section: Preparation Of the 4-oxazolidinonecarbaldehyde Intermediatementioning

confidence: 97%

Enantioselective access to a versatile 4-oxazolidinonecarbaldehyde and application to the synthesis of a cytotoxic jaspine B truncated analogue

Génisson

Lamandé

Salma

et al. 2007

Tetrahedron: Asymmetry

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“…In our hands, this is the first epoxy alcohol that does not provide the corresponding aminodiol by treatment with an amine and titanium tetraisopropoxide [11] [14c] [15]. Quite gratifyingly, however, a totally regio-and stereospecific oxirane-ring opening took place with the same amine but under Crottis conditions [21] (LiClO 4 /MeCN) to afford (2R,3R)-3-(benzhydrylamino)-3-mesityl-1,2-diol 8 in 97% yield (Scheme 3).…”

mentioning

confidence: 99%

Enantioselective Syntheses of Conformationally Rigid, Highly Lipophilic Mesityl-Substituted Amino Acids

Medina

Moyano

Pericàs

et al. 2000

HCA

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Three N‐Boc‐protected amino acids substituted with a mesityl (=2,4,6‐trimethylphenyl) group were synthesized in enantiomerically pure form, either by asymmetric epoxidation or by aminohydroxylation as the source of chirality. The 3‐mesityloxirane‐2‐methanol 7, easily available in high enantiomer purity by Sharpless epoxidation, was converted into 3‐{[(tert‐butoxy)carbonyl]amino}‐3‐mesitylpropane‐1,2‐diol 9 by a regio‐ and stereoselective ring opening with an ammonia equivalent (sodium azide or benzhydrylamine), followed by hydrogenation and in situ treatment with (Boc)2O (Boc=[(tert‐butoxy)carbonyl]) (Scheme 3). Oxidative cleavage of the diol fragment in 9 afforded N‐[(tert‐butoxy)carbonyl]‐α‐mesitylglycine 1 of >99% ee. This amino acid was also prepared in enantiomerically pure form starting from 2,4,6‐trimethylstyrene (11) by a regioselective Sharpless asymmetric aminohydroxylation, followed by a 2,2,6,6‐tetramethylpiperidin‐1‐yloxyl (TEMPO)‐catalyzed oxidation (Scheme 4). On the other hand, 1‐[(tert‐butoxy)carbonyl]‐2‐{{[(tert‐butyl)dimethylsilyl]oxy}methyl}‐3‐mesitylaziridine 14 was prepared from 9 by a sequence involving selective protection of the primary alcohol (as a silyl ether), activation of the secondary alcohol as a mesylate, and base‐induced (NaH) cyclization (Scheme 5). The reductive cleavage of the aziridine ring (H2, Pd/C), followed by alcohol deprotection (Bu4NF/THF) and oxidation (pyridinium dichromate (PDC)/DMF or (TEMPO)/NaClO) provided, in high yield and enantiomeric purity, N‐[(tert‐butoxy)carbonyl]‐β‐mesitylalanine 2. Alternatively, the regioselective ring opening of the aziridine ring of 14 with lithium dimethylcuprate, followed by silyl‐ether cleavage and oxidation lead to N‐[(tert‐butoxy)carbonyl]‐β‐mesityl‐β‐methylalanine 3. A conformational study of the methyl esters of the N‐Boc‐protected amino acids 1 and 3 carried out by variable‐temperature 1H‐NMR and semi‐empirical (AM1) calculations shows the strong rotational restriction imposed by the mesityl group.

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“…Enantiomerically pure oxiranemethanol 7 was treated under Sharpless conditions [20] (Ti(O i Pr) 4 /CH 2 Cl 2 ) using benzhydrylamine ( (diphenylmethyl)amine) as an ammonia surrogate but, quite unexpectedly, without success. In our hands, this is the first epoxy alcohol that does not provide the corresponding aminodiol by treatment with an amine and titanium tetraisopropoxide [11] [14c] [15]. Quite gratifyingly, however, a totally regio-and stereospecific oxirane-ring opening took place with the same amine but under Crottis conditions [21] (LiClO 4 /MeCN) to afford (2R,3R)-3-(benzhydrylamino)-3-mesityl-1,2-diol 8 in 97% yield (Scheme 3).…”

mentioning

confidence: 99%

Enantioselective Syntheses of Conformationally Rigid, Highly Lipophilic Mesityl-Substituted Amino Acids

Medina

Moyano

Pericàs

et al. 2000

HCA

Self Cite

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Three N-Boc-protected amino acids substituted with a mesityl ( 2,4,6-trimethylphenyl) group were synthesized in enantiomerically pure form, either by asymmetric epoxidation or by aminohydroxylation as the source of chirality. The 3-mesityloxirane-2-methanol 7, easily available in high enantiomer purity by Sharpless epoxidation, was converted into 3-{[(tert-butoxy)carbonyl]amino}-3-mesitylpropane-1,2-diol 9 by a regio-and stereoselective ring opening with an ammonia equivalent (sodium azide or benzhydrylamine), followed by hydrogenation and in situ treatment with (Boc) 2 O (Boc [(tert-butoxy)carbonyl]) (Scheme 3). Oxidative cleavage of the diol fragment in 9 afforded N-[(tert-butoxy)carbonyl]-a-mesitylglycine 1 of > 99% ee. This amino acid was also prepared in enantiomerically pure form starting from 2,4,6-trimethylstyrene (11) by a regioselective Sharpless asymmetric aminohydroxylation, followed by a 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO)-catalyzed oxidation (Scheme 4). On the other hand, 1-[(tert-butoxy)carbonyl]-2-{{[(tert-butyl)dimethylsilyl]oxy}methyl}-3-mesitylaziridine 14 was prepared from 9 by a sequence involving selective protection of the primary alcohol (as a silyl ether), activation of the secondary alcohol as a mesylate, and base-induced (NaH) cyclization (Scheme 5). The reductive cleavage of the aziridine ring (H 2 , Pd/C), followed by alcohol deprotection (Bu 4 NF/THF) and oxidation (pyridinium dichromate (PDC)/DMF or (TEMPO)/NaClO) provided, in high yield and enantiomeric purity, N-[(tert-butoxy)carbonyl]-b-mesitylalanine 2. Alternatively, the regioselective ring opening of the aziridine ring of 14 with lithium dimethylcuprate, followed by silyl-ether cleavage and oxidation lead to N-[(tert-butoxy)carbonyl]-b-mesityl-b-methylalanine 3. A conformational study of the methyl esters of the N-Boc-protected amino acids 1 and 3 carried out by variable-temperature 1 H-NMR and semi-empirical (AM1) calculations shows the strong rotational restriction imposed by the mesityl group.

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Regioselective ring opening of chiral epoxyalcohols by primary amines

Cited by 78 publications

References 10 publications

Enantioselective access to a versatile 4-oxazolidinonecarbaldehyde and application to the synthesis of a cytotoxic jaspine B truncated analogue

Enantioselective access to a versatile 4-oxazolidinonecarbaldehyde and application to the synthesis of a cytotoxic jaspine B truncated analogue

Enantioselective Syntheses of Conformationally Rigid, Highly Lipophilic Mesityl-Substituted Amino Acids

Enantioselective Syntheses of Conformationally Rigid, Highly Lipophilic Mesityl-Substituted Amino Acids

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