Asymmetric Mannich-Type Synthesis of N-Phosphinyl α-Aminophosphonic Acid Monoesters

Asymmetric Synthesis of Tetrasubstituted α-Aminophosphonic Acid Derivatives

Due to their structural similarity with natural α-amino acids, α-aminophosphonic acid derivatives are known biologically active molecules. In view of the relevance of tetrasubstituted carbons in nature and medicine and the strong dependence of the biological activity of chiral molecules into their absolute configuration, the synthesis of α-aminophosphonates bearing tetrasubstituted carbons in an asymmetric fashion has grown in interest in the past few decades. In the following lines, the existing literatures for the synthesis of optically active tetrasubstituted α-aminophosphonates are summarized, comprising diastereoselective and enantioselective approaches.

Synthetic strategies of phosphonodepsipeptides

Phosphonodepsipeptides are phosphorus analogues of depsipeptides and phosphonate-linked analogues of naturally occurring peptides. They are more stable than phosphonopeptides and have been widely applied as enzyme inhibitors, haptens for the production of antibodies, biological agents, and prodrugs. The synthetic strategies towards phosphonodepsipeptides are reviewed, including the phosphonylation of hydroxy esters with phosphonochloridates, the condensation of phosphonic monoesters and hydroxy esters, the alkylation of phosphonic monoesters with 1-(alkoxycarbonyl)alkyl halides or sulfonates, multicomponent condensation of amides, aldehydes, and dichlorophosphites followed by alcoholysis with hydroxy esters, the phosphinylation of hydroxy esters with phosphonochloridites followed by oxidation, and the carbene insertion of N-protected amino acids with 1-diazoalkylphosphonates. This review includes the synthesis of α-, β-, and γ-phosphonodepsipeptides and phosphonodepsipeptides with C-1-hydroxyalkylphosphonic acids.

Regioselective BF3·Et2O-catalyzed C–H functionalization of indoles and pyrrole with reaction of α-diazophosphonates

A regioselective synthesis of β-(3-indol)-β-aminophosphonates and β-(2-pyrrol)-β-aminophosphonates was developed through an intermolecular C–H insertion of α-diazophosphonates with indole and pyrrole derivatives catalyzed by BF₃·Et₂O.

Regiospecific and highly stereoselective synthesis of β-amino (Z)-enylphosphonates via β-hydrogen migration reaction of dialkyl α-diazophosphonates catalyzed by AgOTf

The diazo decomposition of dialkyl α-diazophosphonates in the presence of AgOTf provides an efficient one-step route to a variety of β-amino (Z)-enylphosphonates in good yields with complete control over regio- and stereochemistry.

Direct transformation of amides into α-amino phosphonates via a reductive phosphination process

The first general method for the reductive phosphination of amides in one pot has been developed. The reactions described provide a novel access to α-amino phosphonates in good to excellent yields, cover a broad scope of substrates such as secondary and tertiary amides, and do not require a low temperature.

Diastereo- and enantioselective nitro-Mannich reaction of α-substituted nitroacetates to N-phosphoryl imines catalyzed by cinchona alkaloid thiourea organocatalysts

The asymmetric nitro-Mannich reaction of N-phosphoryl imines with α-substituted nitroacetates was performed by using cinchona alkaloid thioureas as organocatalysts in toluene at -20 °C. The present method was highly tolerable to functionalized N-phosphoryl imines and provided a reliable synthetic route to obtain the corresponding β-nitro ethylphosphoramidates with adjacent quaternary and tertiary chiral centers in high yield (up to 86%) and high enantiostereoselectivity (up to 99% ee) and diastereoselectivity (up to 99 : 1, anti-selectivity).