Recent Advances in the Chemistry of the Organotin Hydrides

Catalyst-free photo-induced aerobic radical synthesis of lactams from N-alkenyl trichloroacetamides in 2-methyltetrahydrofuran as the radical initiator under violet light

The first violet light-mediated synthesis of γ- and δ-lactams from N-alkenyl trichloroacetamides is reported in tetrahydrofuran or 2-methyltetrahydrofuran alone. These catalyst and additive-free reactions are achieved with non-anhydrous solvents and under an air atmosphere where the solvent serves as the radical initiator.

Isolable Tin(II) Hydrides Featuring Sterically Undemanding Pincer-Type Ligands and Their Dehydrogenative Sn-Sn Bond Forming Reactions to Distannynes Promoted by Lewis Acidic Tri-sec-butylborane

Unlike isolable tin(II) hydrides supported by bulky ligands reported in the literature, this research describes the synthesis and characterization of thermally stable tin(II) hydrides L^PhSnH (1-H) and ^MeLSnH (2-H) stabilized by sterically undemanding N,N,N-coordinating pincer-type ligands (L^Ph = 2,5-dipyridyl-3,4-diphenylpyrrolato; ^MeL = 2,5-bis(6-methylpyridyl)pyrrolato). The results from previous reports reveal that attempts to access tin(II) hydrides containing less-bulky ligands have had limited success, and decomposition to tin(I) distannynes often occurs. The key to the successful isolation of 1-H and 2-H is the identification of the role of Lewis acidic B^sBu₃, generated upon delivering hydride from commonly used hydride reagents M[B^sBu₃H] ("selectrides", M = Li or K). This study details compelling experimental evidence and theoretical results of the role played by B^sBu₃, which catalyzes the dehydrocoupling reactions of 1-H and 2-H to yield tin(I) distannynes L^PhSn-SnL^Ph (1₂) and ^MeLSn-Sn^MeL (2₂) with the liberation of H₂. To avoid the interference of B^sBu₃, 1-H and 2-H can be isolated in pure forms using pinacolborane as the hydride donor with L^PhSnOMe (1-OMe) and ^MeLSnOMe (2-OMe) as reactants, respectively. DFT calculations and experimental observations indicate that the coordination of the Sn-H bond of 1-H to B^sBu₃ leaves an electrophilic tin center, rendering the nucleophilic attack by the second equivalent of 1-H forming a Sn-Sn bond.

Molecular Main Group Metal Hydrides

This review serves to document advances in the synthesis, versatile bonding, and reactivity of molecular main group metal hydrides within Groups 1, 2, and 12-16. Particular attention will be given to the emerging use of said hydrides in the rapidly expanding field of Main Group element-mediated catalysis. While this review is comprehensive in nature, focus will be given to research appearing in the open literature since 2001.

Evolution towards green radical generation in total synthesis

The use of radicals as intermediates in total synthesis has evolved since their initial use in the latter half of the twentieth century. Radical generation from metal hydride methodologies has shifted to "greener" techniques including catalytic metal-mediated systems, electrochemical and photoredox-mediated processes. This review will focus on these classical and contemporary methods for radical generation and their applications in recent total syntheses.

Hydrodehalogenation of alkyl halides catalyzed by a trichloroniobium complex with a redox active α-diimine ligand

A high-valent d⁰ niobium(v) complex, (α-diimine)NbCl₃ (1), bearing a dianionic redox-active α-diimine ligand served as a catalyst for a hydrodehalogenation reaction of alkyl halides in the presence of PhSiH₃. During the catalytic reaction, the redox-active α-diimine ligand allowed the complex to reversibly release and accept one-electron through switching its coordination mode between a dianionic folded form and a monoanionic planar one.

Investigating the structural chemistry of organotin(IV) compounds: recent advances

Organotin(IV) compounds have been considered for their outstanding industrial, medical and specific applications in the synthesis of various types of chemical compounds. In this review, we have focused on the structural chemistry of organotin(IV) compounds, including coordination chemistry, the effect of structure on reactions, bond formations from the perspective of structure and investigation of the structure of organotin(IV) compounds in different phases. The structural chemistry of organotin(IV) compounds is subject to interest due to their major impact on predicting the properties and drumming up support for pushing back the frontiers of synthesis of organotin(IV) compounds with advanced properties.