Partially acetylated carbohydrates are integral to several biological functions and serve as synthetic intermediates for accessing complex glycoconjugates and oligosaccharides; however, their chemical synthesis remains highly challenging. Herein, we describe a straightforward protocol for the synthesis of monoacetylated sugars through acid-catalyzed regioselective deacetylation of readily accessible peracetylated glycosides featuring a cleavable aglycone (4-methoxyphenyl). The protocol proved effective for β-1,2-trans and α-1,2-cis-configured peracetylated pyranosides and its utility was demonstrated by large-scale synthesis, optimization for continuous flow, and application towards oligosaccharide synthesis.

Non‐typical C‐functionalized sugars represent a prominent yet hardly accessible class of biologically‐active compounds. The available synthetic methodologies toward such sugar derivatives suffer either from an extensive use of protecting groups, requiring long and laborious synthetic manipulations, or from limited predictability and noncontrollable site‐selectivity of the employed C‐functionalization reactions. In this work, we disclose an alternative synthetic methodology toward nontypical sugars that allows facile, site‐selective, and stereocontrolled C‐functionalization of sugars through a traceless tethering approach. The described silyl‐based redox‐active tethering group appends directly to the unprotected sugar substrate and mediates the C‐functionalization reaction through a photochemically‐promoted 1,6‐hydrogen atom transfer (HAT) mechanism, while transforming into a readily‐removable silyl protecting group. The protocol is compatible with a variety of unprotected carbohydrate substrates featuring sensitive aglycons and a diverse set of coupling partners, providing a straightforward and scalable route to pharmaceutically relevant C‐functionalized carbohydrate conjugates.

Aromatic compounds serve as key feedstocks in the chemical industry, typically undergoing functionalization or full reduction. However, partial reduction via dearomative sequences remains underexplored despite its potential to rapidly generate complex three-dimensional scaffolds and the existing dearomative strategies often require metal-mediated multistep processes or suffer from limited applicability. Herein, a photocatalytic radical cascade approach enabling dearomative difunctionalization through selective spirocyclization/imination of nonactivated arenes is reported. The method employs bifunctional oxime esters and carbonates to introduce multiple functional groups in a single step, forming spirocyclic motifs and iminyl functionalities via N–O bond cleavage, hydrogen-atom transfer, radical addition, spirocyclization, and radical-radical cross-coupling. The reaction constructs up to four bonds (C−O, C−C, C−N) from simple starting materials. Its broad applicability is demonstrated on various substrates, including pharmaceuticals, and it is compatible with scale-up under flow conditions, offering a streamlined approach to synthesizing highly decorated three-dimensional frameworks.

Unnatural α-amino acids constitute a fundamental class of biologically relevant compounds. However, despite the interest in these motifs, synthetic strategies have traditionally employed polar retrosynthetic disconnections. These methods typically entail the use of stoichiometric amounts of toxic and highly sensitive reagents, thereby limiting the substrate scope and practicality for scale up. In this work, an efficient protocol for the asymmetric synthesis of unnatural α-amino acids is realized through photoredox-mediated C-O bond activation in oxalate esters of aliphatic alcohols as radical precursors. The developed system uses a chiral glyoxylate-derived N-sulfinyl imine as the radical acceptor and allows facile access to a range of functionalized unnatural α-amino acids through an atom-economical redox-neutral process with CO₂ as the only stoichiometric byproduct.

Herein, we report a silver-catalyzed protocol for decarboxylative cross-coupling between carboxylic acids and isocyanides, leading to linear amide products through a free-radical mechanism. The disclosed approach provides a general entry to a variety of decorated amides, accommodating a diverse array of radical precursors, including aryl, heteroaryl, alkynyl, alkenyl, and alkyl carboxylic acids. Notably, the protocol proved to be efficient for decarboxylative late-stage functionalization of several elaborate pharmaceuticals, demonstrating its potential applications.

Herein, we report a mild and general protocol for chemoselective deacetylation of mixed acetyl- and benzoyl-protected carbohydrates under mild acidic conditions. The protocol allows quick access to partially protected carbohydrates, which serve as versatile synthetic intermediates during the total synthesis of various mono- and oligosaccharide targets. The applicability of the developed protocol was successfully demonstrated on a range of carbohydrate substrates of various configurations and substitution patterns featuring functionalized aliphatic and aromatic aglycones. The protocol has shown excellent compatibility with the widely used O-anomeric protecting groups, prespacer aglycones, and thioglycoside glycosyl donors.

Herein, a straightforward synthetic approach for the construction of phenanthridin-6(5H)-one skeletons is disclosed. The developed protocol relies on palladium catalysis, providing controlled access to a range of functionalized phenanthridin-6(5H)-ones in 59-88% yields. Furthermore, plausible reaction pathways are proposed based on mechanistic experiments.

Noncanonical amino acids (ncAAs) are indispensable tools for engineering peptide structure, function, and pharmacokinetics. Yet, direct, stereoselective access to these motifs from native amines remains limited. We present a unified, photoredox-driven approach for asymmetric α-amino C–H functionalization across various amines. By employing acridinium or decatungstate catalysis to produce α-amino radicals, followed by selective trapping with chiral N-sulfinyl imines, this method yields ncAAs with broad applicability, high yields, and excellent selectivity. The developed technology showcases versatility in ncAA synthesis through late-stage bioconjugation and auxiliary removal while maintaining full stereochemical integrity. The mechanism operates via an oxidation-deprotonation pathway with the acridinium catalyst or through a direct hydrogen atom transfer (d-HAT) or proton-coupled electron transfer (PCET) pathway using decatungstate.