Catalytic Synthesis of β³‐Amino Acid Derivatives from α‐Amino Acids

Abstract

α goes to β! The catalytic ring‐expansive carbonylation of oxazolines, easily derived from α‐amino acids, to yield β‐amino acid derivatives is described. The catalyst is [HCo(CO)4]; high yields are observed for most substrates, and enantiopure oxazolines are carbonylated with predictable stereochemistry to the corresponding enantiopure oxazinones.

Effects of Structural Variations on the Cellular Response and Mechanical Properties of Biocompatible, Biodegradable, and Porous Smectic Liquid Crystal Elastomers

“…There are numerous examples of both natural and synthetic polymer systems that have been used as cell scaffolds . Synthetic biodegradable polymers based on poly(ε‐caprolactone), poly(lactic acid), poly(glycolide), poly( p ‐dioxanone), poly(carbonates), and poly(α‐amino acids) as well as copolymers made of these building blocks have been explored to create cell scaffolds for applications such as implants, stents, sutures, in drug delivery, wound dressings, as injectable ECMs, and in multiple other clinical applications . Key advantages of these materials are the possibilities to easily tailor their chemical and mechanical properties as well as biodegradation simply by introducing small changes in their chemical compositions .…”

“…[3][4][5][6][7] Synthetic biodegradable polymers based on poly(ε-caprolactone), poly(lactic acid), poly(glycolide), poly(p-dioxanone), poly(carbonates), and poly(α-amino acids) as well as copolymers made of these building blocks have been explored to create cell scaffolds for applications such as implants, stents, sutures, in drug delivery, wound dressings, as injectable ECMs, and in multiple other clinical applications. [8][9][10][11][12][13][14][15][16] Key advantages of these materials are the possibilities to easily tailor their chemical and mechanical properties as well as biodegradation simply by introducing small changes in their chemical compositions. [4,6,17] However, the structural space for these materials is massive and further modifications, for example by introducing entirely new physical properties, could result in tunable and new, unexpected cell-scaffold interactions.…”

Asymmetric Synthesis of β2‐Aryl Amino Acids through Pd‐Catalyzed Enantiospecific and Regioselective Ring‐Opening Suzuki–Miyaura Arylation of Aziridine‐2‐carboxylates

“…Therefore, the asymmetric synthesis of β‐amino acids has attracted much attention over the last few decades . Currently, β 3 ‐amino acids (i.e., β‐substituted β‐amino acids) are readily accessible through a variety of homologations (e.g., Arndt–Eistert homologation, Kowalski ester homologation, Coates oxazoline carbonylation, and Kolbe reaction) of α‐amino acid derivatives. Thus, most of the β 3 ‐amino acids with proteogenic substituents are commercially available.…”

Aminomethylation of chiral silyl enol ethers: access to β2-homotryptophane and β2-homolysine derivatives

“…b 3 -Amino acids are readily available in enantiomerically pure form by homologation strategies of a-amino acids. For instance, a recent catalytic homologation of a-amino acids via the carbonylation of enantiopure oxazolines using a silylcobalt precatalyst has been reported by Coates et al 5 However the methodology describes only the synthesis of non-functionalized b 3 -amino acids, that is, bearing alkyl or phenyl chains. Noticeably, the Arndt-Eistert homologation of a-amino acids allows in few steps the preparation of b 3 -amino acids bearing functional groups on their side chains.…”