Synthesis of highly functionalized β-aminocyclopentanecarboxylate stereoisomers by reductive ring opening reaction of isoxazolines

Application of 2-Azabicyclo[2.2.1]Hept-5-En-3-One (Vince Lactam) in Synthetic Organic and Medicinal Chemistry

2-Azabicyclo[2.2.1]hept-5-en-3-one (Vince lactam) is known to be a valuable building block in synthetic organic chemistry and drug research. It is an important precursor to access of some blockbuster antiviral drugs such as Carbovir or Abacavir as well as other carbocyclic neuraminidase inhibitors as antiviral agents. The ring C=C bond of the Vince lactam allows versatile chemical manipulations to create not only functionalized γ-lactams, but also γ-amino acid derivatives with a cyclopentane framework. The aim of the current account is to summarize the chemistry of Vince lactam, its synthetic utility and application in organic and medicinal chemistry over the last decade.

Diversity-Oriented Synthesis of Highly Functionalized Alicycles across Dipolar Cycloaddition/Metathesis Reaction

This Account gives an insight into the selective functionalization of some readily available commercial cyclodienes across simple chemical transformations into functionalized small-molecular scaffolds. The syntheses involved selective cycloadditions, followed by ring-opening metathesis (ROM) of the resulting azetidin-2-one derivatives or isoxazoline frameworks and selective cross metathesis (CM) by discrimination of the C=C bonds on the alkenylated heterocycles. The CM protocols have been described when investigated under various conditions with the purpose on exploring chemodifferentiation of the olefin bonds and a study on the access of the corresponding functionalized β-lactam or isoxazoline derivatives is presented. Due to the expanding importance of organofluorine chemistry in drug research as well as of the high biological potential of β-lactam derivatives several illustrative examples to the access of some fluorine-containing molecular entities is also presented in this synopsis.

1 Introduction

2 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Chlorosulfonyl Isocyanate Cycloaddition

3 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Nitrile Oxide Cycloaddition

4 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Metathesis

5 Functionalization of sSome Cyclodienes across Nitrile Oxide Cycloaddition

6 Selective Synthesis of Functionalized Alicycles across Ring-Opening Metathesis

7 Selective Synthesis of Functionalized Alicycles through Cross Metathesis

8 Summary and Outlook

9 List of Abbreviations

Synthesis and Biological Activity of 2-(2-Amino-2-phenylethyl)-5-oxotetrahydrofuran-2-carboxylic Acid: A Microwave-Assisted 1,3-Dipolar Cycloaddition Approach

The microwave-assisted 1,3-dipolar cycloaddition of furanyl and benzyl oximes and several methyl acrylates effectively provided several isoxazoline when mediated by diacetoxyiodobenzene. The selected isoxazoline, methyl-5-(3-methoxy-3-oxopropyl)-3-phenyl-4,5-dihydro isoxazole-5-carboxylate, was rapidly transformed to the γ-lactone carboxylic acid, 2-(2-amino-2-phenylethyl)-5-oxotetrahydrofuran-2-carboxylic acid, in reasonable yield. The biological activity of this γ-lactone carboxylic acid increased the growth of E. coli organisms by about 44% and has a potential significance in stem cell research.

Diversity-oriented Functionalization of Cyclodienes Through Selective Cycloaddition/Ring-opening/Cross-metathesis Protocols; Transformation of a "Flatland" into Three-dimensional Scaffolds With Stereo- and Regiocontrol

This article presents selective transformations of some readily available cyclodienes through simple chemical procedures into novel functionalized small-molecular entities. The syntheses hereby described involved selective cycloadditions, followed by ring-opening metathesis of the resulting β-lactam or isoxazoline derivatives and selective cross-metathesis by differentiation of the olefin bonds on the alkenylated heterocycles. The cross-metathesis transformations have been detailed, which were performed under various experimental conditions with the aim of exploring chemodiscrimination of the olefin bonds and delivering the corresponding functionalized β-lactam or isoxazoline derivatives.

Highly functionalized cyclic β-amino acid moieties as promising scaffolds in peptide research and drug design

Peptide-based drug research has received high attention in the field of medicinal chemistry over the past decade. For drug design, to improve proteolytic stability, it is desirable to include unnatural building blocks, such as conformationally restricted β-amino acid moieties, into the peptide sequence. Accordingly, the synthesis and incorporation of such conformationally rigid systems into novel type of peptides has gained large interest. Our research group has designed highly efficient methods for the construction of potential antimicrobial peptides. Moreover, a number of synthetic approaches have been developed for the synthesis of various pharmacologically interesting cyclic β-amino acid derivatives as monomers with multiple stereogenic centers.

A one-pot synthesis of 3-trifluoromethyl-2-isoxazolines from trifluoromethyl aldoxime

Functionalized 3-trifluoromethyl-2-isoxazolines and 3-trifluoromethylisoxazoles were easily prepared from trifluoromethyl aldoxime 2 under mild conditions by using DIB as oxidant. Theoretical studies of the reactivity of trifluoroacetonitrile oxide 4 toward olefins and alkynes were carried out. The 3-trifluoromethyl-2-isoxazolines were ring-opened with NaBH4 and NiCl2 to yield the corresponding trifluoromethylated γ-amino alcohols.

Efficient regio- and stereoselective access to novel fluorinated β-aminocyclohexanecarboxylates

A regio- and stereoselective method has been developed for the synthesis of novel fluorinated 2-aminocyclohexanecarboxylic acid derivatives with the fluorine attached to position 4 of the ring. The synthesis starts from either cis- or trans-β-aminocyclohex-4-enecarboxylic acids and involves regio- and stereoselective transformation of the ring C–C double bond through iodooxazine formation and hydroxylation, followed by hydroxy–fluorine or oxo–fluorine exchange.

Synthesis of highly functionalized fluorinated cispentacin derivatives

Fluorinated highly functionalized cispentacin derivatives were synthetised starting from an unsaturated bicyclic β-lactam through C=C bond functionalization via the dipolar cycloaddition of a nitrile oxide, isoxazoline opening, and fluorination by OH/F exchange.