156643-23-1

We present here an efficient method for the hydroboration of aldimines (-C=N-) with pinacolborane (HBpin) using an alkali metal catalyst, potassium benzyl. The reaction was accomplished with unprecedented catalytic efficiency under mild and solvent-free conditions to afford the high yield of the corresponding N-boryl amines up to 97percent. Various functionalities on aldimines were incorporated for hydroboration. The corresponding boryl amines were subjected to further hydrolysis to yield the corresponding secondary amines with good yields up to 89percent. This protocol for the reaction demonstrates an atom-economic and green method with diverse imines that bears excellent functional group tolerance. Chemoselective reduction of imines was also attained, with good yields of 74–89percent. We also propose the most plausible mechanism involving the formation of metal hydride as the active pre-catalyst.

Pd-Catalyzed enantioselective C(sp3)-H arylation of N-(o-Br-aryl) anilides has been disclosed, and quaternary α-nitro amides were constructed with up to 98% ee. The presence of the nitro group on the substrate enables the progress of the reaction and the ready transformation of the product to optically active quaternary amino acid derivatives.

The alkylation of amines by alcohols is a broadly applicable, sustainable, and selective method for the synthesis of alkyl amines, which are important bulk and fine chemicals, pharmaceuticals, and agrochemicals. We show that Cr complexes can catalyze this C?N bond formation reaction. We synthesized and isolated 35 examples of alkylated amines, including 13 previously undisclosed products, and the use of amino alcohols as alkylating agents was demonstrated. The catalyst tolerates numerous functional groups, including hydrogenation-sensitive examples. Compared to many other alcohol-based amine alkylation methods, where a stoichiometric amount of base is required, our Cr-based catalyst system gives yields higher than 90 % for various alkyl amines with a catalytic amount of base. Our study indicates that Cr complexes can catalyze borrowing hydrogen or hydrogen autotransfer reactions and could thus be an alternative to Fe, Co, and Mn, or noble metals in (de)hydrogenation catalysis.

A range of alternative, more environmentally conservative solvents have been evaluated for use within the direct reductive amination reactions of aldehydes using borane-based reductants. The data generated has been used to develop a guide to facilitate replacement of less desirable chlorinated solvents, such as DCE, from these widely used synthetic processes.

A domino palladium-catalyzed Heck-intermolecular direct arylation reaction has been developed, giving access to a variety of dihydrobenzofurans, indolines, and oxindoles. A variety of sulfur-containing heterocycles such as thiazoles, thiophenes, and benzo

An efficient and highly stereoselective total synthesis of the natural product (±)-welwitindolinone A isonitrile (1) is described. The bicyclo[4.2.0]octane core of 1 was established by a regio- and diastereoselective [2+2] ketene cycloaddition. The C12 quaternary center and vicinal stereogenic chlorine were installed in a single operation with excellent stereocontrol via a chloronium ion mediated semipinacol rearrangement. Described strategies for construction of the spiro-oxinole include a Sml 2-LiCl mediated reductive cyclization and a novel anionic cyclization that simultaneously constructs the spiro-oxindole and vinyl isonitrile moieties.

The copper-catalyzed intramolecular N-arylation of 2-bromoarylureas performed in water leading to the benzo[d]imidazolone framework is reported. The scope of the methodology presented herein proved to?be broad and afforded a significant number of benzoimidazolones in good to excellent yields. The reported protocol is based on the use of CuI and TMEDA acting both as the ligand and as the base in a water solution, which allows for the easy separation of the catalyst containing aqueous phase from the products by simple extraction. Additionally, the N- versus O-arylation competitive processes are also discussed.