α-Aminocarbene-Mediated Si-H Insertion: Deoxygenative Silylation of Aromatic Amides with Silanes.

While metal carbene-mediated Si-H insertion reactions have become a powerful strategy to build new C-Si bonds, the utilization of α-aminocarbene intermediates generated from readily available precursors in the Si-H insertion reaction remains a longstanding challenge. Herein, we develop a practical and general strategy to synthesize α-aminosilanes through a deoxygenative cross-coupling of amides and silanes mediated by Sm/SmI2. Given the simplicity and versatility, this methodology represents a fascinating example for the effective utilization of inert amides as α-aminocarbene precursors in organic synthesis.

Merging Electron Transfer with 1,2-Metalate Rearrangement: Deoxygenative Arylation of Aromatic Amides with Arylboronic Esters.

Amides are essentially inert carboxyl derivatives in many types of chemical transformations. In particular, deoxygenative C-C bond formation of amides to synthetically important amines is a long-standing challenge for synthetic chemists due to the inertness of the resonance-stabilized amide C=O bond. Herein, it is disclosed that by merging electron-transfer-induced activation with 1,2-metalate rearrangement, a wide range of aromatic amides react smoothly with arylboron reagents, affording a series of biologically relevant diarylmethylamines as deoxygenative C-C bond cross-coupling products. With its simplicity and versatility, this reaction shows great promise in the synthesis of amines from amides, which may open up new avenues in retrosynthetic planning and find widespread use in academia and industry.

Iron(III)/Copper(II)-Cocatalyzed Cycloaddition/[3,3]-Rearrangement/N-O Bond Cleavage To Prepare Polysubstituted Pyrrolizines from N-Vinyl-α,ß-Unsaturated Nitrones and Activated Alkynes.

An efficient one-pot synthesis of polysubstituted pyrrolizines from N-vinyl- α,ß-unsaturated nitrones and activated alkynes through iron(III)/copper(II)-cocatalyzed [3 + 2] cycloaddition/[3,3]-rearrangement and sequential N-O bond cleavage was developed. The reaction first underwent [3 + 2] cycloaddition and [3,3]-rearrangement to afford nine-membered N-heterocycles, and then a controlled N-O bond cleavage of nine-membered rings by iron(III)/copper(II) cocatalysts delivered pyrrolizine scaffolds. A kinetic resolution of nine-membered ring compounds was achieved for the first time by using copper(II) acetate combined with a chiral PyBox ligand.