Visible-light-mediated decarboxylative benzoyloxylation of β-hydroxy amino acids and its application to synthesis of functional 1,2-amino alcohol derivatives

Triflic Anhydride Promoted Decarboxylative Functionalization of α-Amino Acids

The decarboxylation of naturally abundant amino acids, followed by subsequent inter- or intramolecular reaction cascades, enables the rapid synthesis of a variety of diverse and high-value amine derivatives. Previous methods have relied heavily on transition metals, involved tedious procedures, or required harsh conditions. Herein, we present a novel reaction cascade for the decarboxylation and nucleophilic functionalization of α-amino acids. This method is characterized by being transition-metal-free, convenient to operate, environmentally friendly and having mild conditions.

Regioselective benzoyloxylative dearomatization of naphthols by benzoyl peroxide under catalyst-free conditions

A direct regioselective benzoyloxylative dearomatization of both α- and β-naphthols by benzoyl peroxide under an air atmosphere, and radical inhibitor- and catalyst-free conditions at room temperature is described. The methodology provides a new efficient strategy for the construction of α-ketol derivatives bearing an oxo-quaternary carbon center from naphthols with good to excellent yields.

Small peptide diversification through photoredox-catalyzed oxidative C-terminal modification

A photoredox-catalyzed oxidative decarboxylative coupling of small peptides is reported, giving access to a variety of N,O-acetals. They were used as intermediates for the addition of phenols and indoles, leading to novel peptide scaffolds and bioconjugates. Amino acids with nucleophilic side chains, such as serine, threonine, tyrosine and tryptophan, could also be used as partners to access tri- and tetrapeptide derivatives with non-natural cross-linking.

Recent advances in reactions using diacyl peroxides as sources of O- and C-functional groups

This review summarizes recent advances in reactions utilizing diacyl peroxides as O- and C-sources, with examples illustrating how the reactivity of diacyl peroxides in organic reactions can be controlled.

Total Synthesis of Zephycarinatines via Photocatalytic Reductive Radical ipso-Cyclization

We report herein a nonbiomimetic strategy for the total synthesis of the plicamine-type alkaloids zephycarinatines C and D. The key feature of the synthesis is a stereoselective reductive radical ipso-cyclization using visible-light-mediated photoredox catalysis. This cyclization enabled the construction of a 6,6-spirocyclic core structure through the addition of a carbon-centered radical onto the aromatic ring. Biological evaluation of zephycarinatines and their derivatives revealed that the synthetic derivative with a keto group displays moderate inhibitory activity against LPS-induced NO production. This approach could offer future opportunities to expand the chemical diversity of plicamine-type alkaloids as well as providing useful intermediates for their syntheses.

Total Synthesis of (+)-Polyoxamic Acid via Visible-Light-Mediated Photocatalytic β-Scission and 1,5-Hydrogen Atom Transfer of Glucose Derivative

A total synthesis of polyoxamic acid has been achieved. The key feature of the synthetic route is a visible-light-mediated β-scission and carbon-to-carbon 1,5-hydrogen atom transfer (1,5-HAT) to provide the functionalized alditol under mild conditions. This type of carbon-to-carbon 1,5-HAT initiated by C(sp³)-centered radicals has been scarcely reported. Furthermore, the reaction was adapted for flow chemistry, facilitating the total synthesis of polyoxamic acid.