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The study introduces a previously unidentified method for amide bond formation that addresses several limitations of conventional approaches. It uses the β-silyl alkynoate molecule, where the alkynyl group activates the ester for efficient amide formation, while the bulky TIPS (triisopropylsilane) group prevents unwanted 1,4-addition reactions. This approach exhibits high chemoselectivity for amines, making the method compatible with a wide range of substrates, including secondary amines, and targets the specific ε-amino group of lysine among the native amino ester's derivatives. It maintains stereochemistry during amide bond formation and TIPS group removal, allowing a versatile platform for postsynthesis modifications such as click reactions and peptide-drug conjugations. These advancements hold substantial promise for pharmaceutical development and peptide engineering, opening avenues for research applications.

Lead-free metal halide perovskites can potentially be air- and water-stable photocatalysts for organic synthesis, but there are limited studies on them for this application. Separately, machine learning (ML), a critical subfield of artificial intelligence, has played a pivotal role in identifying correlations and formulating predictions based on extensive datasets. Herein, an iterative workflow by incorporating high-throughput experimental data with ML to discover new lead-free metal halide perovskite photocatalysts for the aerobic oxidation of styrene is described. Through six rounds of ML optimization guided by SHapley Additive exPlanations (SHAP) analysis, BA 2 CsAg 0.95 Na 0.05 BiBr 7 as a photocatalyst that afforded an 80% yield of benzoic acid under the standard conditions is identified, which is a 13-fold improvement compared to the 6% with when using Cs 2 AgBiBr 6 as the initial photocatalyst benchmark that is started. BA 2 CsAg 0.95 Na 0.05 BiBr 7 can tolerate various functional groups with 22 styrene derivatives, highlighting the generality of the photocatalytic properties demonstrated. Radical scavenging studies and density functional theory calculations revealed that the formation of the reactive oxygen species superoxide and singlet oxygen in the presence of BA 2 CsAg 0.95 Na 0.05 BiBr 7 are critical for photocatalysis., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

In organic synthesis, transition-metal and photoredox-catalysis-based reaction systems are emerging trends for the construction of C-S bonds. Many review articles have recently appeared in this field; however, we present herein an overview of metal-free C-S coupling reactions using thiols or disulfides as sulfur surrogates. The oxidants we have considered include peroxides, tert-butyl nitrite (TBN), DDQ, iodine reagents, and molecular oxygen. In addition, selective electrochemical oxidative transformations are also covered with mechanistic details.

Organosulfur compounds are omnipresent in many drugs, natural products, and functional materials; therefore, methodologies of C-S bond formation reactions are desirable in synthesis. The recent trend to control many chemical reactions by cooperative multiple weak interactions have emerged as one of the popular topics in supramolecular catalysis. Herein, we have made a collection of literature which utilizes multiple noncovalent interactions like H-bonding, solvent bonding, S-H···π, C-H···π, π-π stacking, charge-transfer complexation, etc. toward aryl C-S bond-formation reactions.

We report herein the use of 9-mesityl-10-methylacridinium perchlorate as the visible-light photocatalyst for dithioacetalization or thioetherification of benzyl alcohols in one pot using aerial dioxygen as a terminal oxidant. EPR analysis and Stern-Volmer quenching studies helped to rationalize the single electron transfer (SET) mechanism.

Herein, we show exclusive control of stereo and regioselective thiol-yne click (TYC) reactions of internal alkynes via amide hydrogen bond control. By exploiting appropriate hydrogen bonding interactions like N-HS, N-HN and C-HO, either (Z)-selective anti-Markovnikov or Markovnikov products could be obtained for an internal alkyne, exclusively.

An umpolung approach for the synthesis of unsymmetrical disulfides via sulfenium ion is reported. In situ generated electrophilic sulfenium ion from electron-rich thiols reacted with second thiols to yield unsymmetrical disulfides. Using an iodine catalyst and 4-dimethylaminopyridine (DMAP)/water as promoter, the target syntheses were achieved in one pot under aerobic condition., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Markovnikov or anti-Markovnikov selective thiol-ene click (TEC) reactions and the synthesis of β-hydroxysulfides via aerial dioxygen activation are prevalent C-S bond forming reactions of styrenes and thiophenols. Herein, by choosing appropriate environments using solvents with additives or neat conditions, any one of these three reactions was achieved exclusively in excellent yields.