One-pot diastereoselective synthesis of α-aminonitriles from aldehydes, chiral amines, and trimethylsilyl cyanide under solvent-free conditions

Efficient Three-Component Strecker Reaction of Aldehydes/Ketones via NHC-Amidate Palladium(II) Complex Catalysis

“…For example, an electron-withdrawing substituent (entries 2 and 9) was compatible with these conditions, as were heteroatom-containing aldehydes (entries 3−5 and 10−12) and aliphatic aldehydes (entries 7, 14, and 15). Similar to previous reports using other Lewis acid catalysts, aromatic (entries 1−7) and aliphatic (entries 8−15) amines were compatible with these reactions as well. ,− Without the use of a desiccating agent, the formation of the imine intermediate was hindered, and low conversion to the α-aminonitrile produt was observed (not shown).…”

“…Often with these substrates, the reaction is carried out stepwise using premade imines or under high pressure conditions 11. Although recently one-pot procedures have been developed for the synthesis of α-aminonitriles using a variety of Lewis acids; such as lithium perchlorate,12 scandium triflate,13 vanadyl triflate,14 zinc halides,15 ytterbium triflate,16 and montmorillonite;17 most of these methods involve the use of strong acidic conditions, expensive reagents, extended reaction times, harsh conditions, fast hydrolysis, and tedious workup leading to the generation of a large amount of waste. Therefore, more general and milder reaction conditions for one-pot multi-component Strecker reactions, particularly those involving ketones, would be advantageous.…”

“…Similar to previous reports using other Lewis acid catalysts, aromatic (entries 1-7) and aliphatic (entries 8-15) amines were compatible with these reactions as well. 7,[12][13][14][15][16][17] Without the use of a desiccating agent, the formation of the imine intermediate was hindered, and low conversion to the R-aminonitrile produt was observed (not shown).…”

Synthesis of α‐Amino Nitriles from Carbonyl Compounds, Amines, and Trimethylsilyl Cyanide: Comparison between Catalyst‐Free Conditions and the Presence of Tin Ion‐Exchanged Montmorillonite

“…Moreover, Lewis acid catalysts such as nickel, [4] thallium, [5] copper, [6] rhodium, [7] niobium, [8] indium, [9] and zinc [10] salts are prone to rapid hydrolysis and consequent deactivation by water released during the course of the reaction and hence are not reusable, resulting in the production of large quantities of inorganic waste. To overcome these disadvantages, the development of heterogeneous catalyst systems has been focused on.…”

Zinc Complexes of β‐Ketoiminato Ligands as Efficient Catalysts for the Synthesis of α‐Amino Nitriles via Strecker Reaction

“…However, the reaction needs high catalysts loading (50 mol%) and has limited substrate scopes. [43] Thus, the use of zinc complex as a catalyst provides eco-friendly, cheap, easily available, bench stable and nontoxic [44] alternatives in various organic reactions. In the course of our ongoing research, we have developed various earth-abundant metal catalysts for many organic transformations such as hydoamination, [45] hydrosilylation, [46] and hydroboration, [47] of various unsaturated moieties.…”