N-Phosphinoylimines: An Emerging Class of Reactive Intermediates for Stereoselective Organic Synthesis

Abstract

N-Phosphinoylimines have recently begun to attract significant attention from synthetic chemists for the preparation of nitrogen-containing molecules. Several methods have been developed for the synthesis, or in situ generation, of these reactive electrophilic species. N-Phosphinoylimines undergo a wide range of reactions, including nucleophilic additions and cycloadditions. These imines are also effective electrophiles in a number of diastereoselective and enantioselective reactions. An advantage of using N-phosphinoylimines is that the reaction products can be easily deprotected under mild acidic conditions, leading to amines. This review outlines the preparation and uses of N-phosphinoylimines with particular emphasis on their applications in stereoselective processes.

Studies on the Bisoxazoline‐ and (−)‐Sparteine‐Mediated Enantioselective Addition of Organolithium Reagents to Imines

“…[11] Among these, the acylimines, [12] sulfonylimines, [13] and especially the phosphinoylimines [14] have found extensive use in catalytic, enantioselective additions of copper and zinc reagents and this field has been extensively reviewed. [15,16] Although organolithium reagents were among the first to be studied they have received less attention in recent years, primarily because of their hyperreactivity and lesser functional group compatibility.…”

Direkte katalytische asymmetrische Reaktionen unter Protonentransferkatalyse

“…[70] Unter milden basischen Bedingungen wird das Thioamidenolat durch die weiche Lewis-Säure Cu I , die einen chiralen Bisphosphanliganden trägt, erzeugt. Das so gebildete chirale Cu-Thioamidenolat nimmt an einer enantioselektiven C-C-Bindungsbildung mit dem N-Dpp-Aldimin 43 teil [53] und liefert das Mannich-Produkt 44 unter Protonentransferbedingungen (Schema 16). Ein anti-diastereoselektiver Verlauf wurde beobachtet, wenn die Reaktion mit dem von Propionsäure abgeleiteten Thiomamid als Pränucleophil ausgeführt wird.…”

A convenient and practical method for the synthesis of N‐thiophosphoryl aldimines and ketimines

“…The introduction of a phosphoryl group modulates the reactivity of the imines, and the phosphoryl group can be easily removed through acid-catalyzed hydrolysis under mild condi- tions [5]. Because of these advantages, N-phosphoryl imines have recently begun to draw much attention of synthetic chemists and have been successfully employed in a variety of asymmetric reactions [4], such as hydrogenation, alkylation, the Mannich reaction, the aza-Henry reaction, and the Strecker reaction. However, N-phosphoryl imines used in the aforementioned reactions are limited to diphenylphosphinoylimines.…”

“…Recently, significant progress has been witnessed in this area [1]. To increase the electrophilic activity of the C N double bond of imines, electronwithdrawing groups, for example, acyl [2], sulfonyl [3], and phosphoryl [4], are often introduced on the nitrogen atom. The introduction of a phosphoryl group modulates the reactivity of the imines, and the phosphoryl group can be easily removed through acid-catalyzed hydrolysis under mild condi- tions [5].…”