Long-range diastereoselectivity in Ugi reactions of 2-substituted dihydrobenzoxazepines

Banfi, Luca; Basso, Andrea; Cerulli, Valentina; Rocca, Valeria; Riva, Renata

doi:10.3762/bjoc.7.109

Cited by 22 publications

(15 citation statements)

References 25 publications

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“…In 1988, Kunz 25 and his group reported a stereoselective synthesis of N-galactosyl-amino acid amide derivative 58a-c via Ugi reaction of β-D-galactopyranosylamines 57, aldehydes and isocyanides in presence of catalytic amount Lewis acid (Scheme 32). The reaction proceeded smoothly to give product with satisfactory yields and high diastereoselectivity.…”

Section: Scheme 31 23 Chiral Amine As Substratesmentioning

confidence: 99%

A concise review on the stereoselective synthesis of chiral α-bisamides using stereoselective Ugi-type reaction

Ramakrishna¹,

Pradhan²

2021

Arkivoc

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To ensure a sustainable development, the "twelve principles of green chemistry" have been proposed for the field of synthetic organic chemistry. The stereoselective Ugi reaction is one of the most widely used reactions with high atom economy to prepare chiral α-bisamides and this reaction satisfies many of the green chemistry principles. The recent achievements in this reaction include one pot synthetic methodology, aqueous phase transformations and solvent free transformations even at ambient conditions. This review summarizes the progress recorded in this field over the past 20 years.Retrosynthetic methodology for the synthesis of Chiral α-bisamide

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Section: Scheme 31 23 Chiral Amine As Substratesmentioning

confidence: 99%

A concise review on the stereoselective synthesis of chiral α-bisamides using stereoselective Ugi-type reaction

Ramakrishna¹,

Pradhan²

2021

Arkivoc

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“…These reactions are typically conducted in polar protic solvents such as methanol or water. Several examples of diastereoselective U-4CR have been described [48][49][50][51][52][53][54]. Yet, the Ugi reaction turned out to be a rather challenging chemical transformation in terms of establishing the asymmetric version [33][34][35].…”

Section: Asymmetric Protocolmentioning

confidence: 99%

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

Wang

Peshkov

et al. 2020

Beilstein J. Org. Chem.

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In this report, we introduce a new strategy for controlling the stereochemistry in Ugi adducts. Instead of controlling stereochemistry directly during the Ugi reaction we have attempted to stereodefine the chiral center at the peptidyl position through the post-Ugi functionalization. In order to achieve this, we chose to study 2-oxo-aldehyde-derived Ugi adducts many of which partially or fully exist in the enol form that lacks the aforementioned chiral center. This in turn led to their increased nucleophilicity as compared to the standard Ugi adducts. As such, the stereocenter at the peptidyl position could be installed and stereodefined through the reaction with a suitable electrophile. Towards this end, we were able to deploy an asymmetric cinchona alkaloid-promoted electrophilic fluorination producing enantioenriched post-Ugi adducts fluorinated at the peptidyl position.

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“…Subsequent reduction and deprotection resulted in the cyclic imines 281 [210]. Then an additional Joullié–Ugi reaction provided the final bicyclic mimics 282 in good to excellent yields, (24–45%) with a preference for the cis -isomer.…”

Section: Reviewmentioning

confidence: 99%

“…In contrast, dihydro-1,4-benzoxazepines 282 ( Scheme 81 ) could be obtained in four-steps by first performing the Mitsunobu reaction with racemic alcohols and the Weinreb hydroxamate 278 . Subsequent reduction and deprotection resulted in the cyclic imines 281 [ 210 ]. Then an additional Joullié–Ugi reaction provided the final bicyclic mimics 282 in good to excellent yields, (24–45%) with a preference for the cis -isomer.…”

Section: Reviewmentioning

confidence: 99%

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

Koopmanschap¹,

Ruijter²,

Orru³

2014

Beilstein J. Org. Chem.

230

117

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SummaryIn the recent past, the design and synthesis of peptide mimics (peptidomimetics) has received much attention. This because they have shown in many cases enhanced pharmacological properties over their natural peptide analogues. In particular, the incorporation of cyclic constructs into peptides is of high interest as they reduce the flexibility of the peptide enhancing often affinity for a certain receptor. Moreover, these cyclic mimics force the molecule into a well-defined secondary structure. Constraint structural and conformational features are often found in biological active peptides. For the synthesis of cyclic constrained peptidomimetics usually a sequence of multiple reactions has been applied, which makes it difficult to easily introduce structural diversity necessary for fine tuning the biological activity. A promising approach to tackle this problem is the use of multicomponent reactions (MCRs), because they can introduce both structural diversity and molecular complexity in only one step. Among the MCRs, the isocyanide-based multicomponent reactions (IMCRs) are most relevant for the synthesis of peptidomimetics because they provide peptide-like products. However, these IMCRs usually give linear products and in order to obtain cyclic constrained peptidomimetics, the acyclic products have to be cyclized via additional cyclization strategies. This is possible via incorporation of bifunctional substrates into the initial IMCR. Examples of such bifunctional groups are N-protected amino acids, convertible isocyanides or MCR-components that bear an additional alkene, alkyne or azide moiety and can be cyclized via either a deprotection–cyclization strategy, a ring-closing metathesis, a 1,3-dipolar cycloaddition or even via a sequence of multiple multicomponent reactions. The sequential IMCR-cyclization reactions can afford small cyclic peptide mimics (ranging from four- to seven-membered rings), medium-sized cyclic constructs or peptidic macrocycles (>12 membered rings). This review describes the developments since 2002 of IMCRs-cyclization strategies towards a wide variety of small cyclic mimics, medium sized cyclic constructs and macrocyclic peptidomimetics.

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Long-range diastereoselectivity in Ugi reactions of 2-substituted dihydrobenzoxazepines

Cited by 22 publications

References 25 publications

A concise review on the stereoselective synthesis of chiral α-bisamides using stereoselective Ugi-type reaction

A concise review on the stereoselective synthesis of chiral α-bisamides using stereoselective Ugi-type reaction

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

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