Phosphorylating Power of Red Phosphorus towards Aldehydes in Basic and in Acidic Media

Abstract

The reactivity of red phosphorus towards aldehydes was investigated under basic and acidic media. It was demonstrated that the real phosphorylating agent involved in the reaction was phosphane (PH3) in basic media, and hypophosphorous acid (H3PO2) in acidic media. A convenient one‐pot synthesis of (α‐hydroxyalkyl)phosphinic acids from red phosphorus and aldehydes in basic media was realized under sonication. The same reaction under acidic media in the presence of hydriodic acid led to the corresponding phosphonic acids. The (α‐hydroxyalkyl)phosphinic acids were readily prepared under sonication from hypophosphorous acid and aldehydes in the presence of catalytic amounts of hydrochloric acid. The mechanism of the addition reaction of PH3 to benzaldehyde was elucidated and shows the complexity of the reaction as a function of the experimental conditions.

A Synthetic Study of Chiral α‐Hydroxy‐H‐Phosphinates Based on Proline Catalysis

“…To initiate our investigations, we examined the reaction of ethyl benzoyl(diethoxymethyl)phosphinate (1 a) and acetone with l-proline as the catalyst. The effects of catalyst loading ( [12][13][14][15]. With 20 mol % l-proline and HCOOH at 0-5 8C (Table 1, entry 14) or 10 mol % l-proline and ACOH at 0-5 8C ( Table 1, entry 15), good yields and high ee values were achieved for both of the two diastereomers.…”

“…Although the migration of an α‐oxygen atom from carbon to phosphorus atoms under a strongly acid medium is common for derivatives of tervalent phosphorus, this phenomenon is unusual for other organophosphorus compounds. As far as we know, only one reaction has been reported for such a process: the transformation of phosphinic acid to phosphonic acid in the presence of hydriodic acid 12. Nevertheless, most of the reactions were performed under strongly acidic conditions with elevated temperature.…”

Novel Method for the Synthesis of α-Amino-α′-hydroxyalkylphosphinic Acids and Bis(α-aminoalkyl)phosphinic Acids: Nuclephilic Addition of α-Hydroxy-H-phosphinic Acids to Diimines

“…On the basis of literature reports for the activation of phosphinic acids [17][18][19] and the reactions reported for diimines, 20 we believe that the present process proceeds via the activation of α-hydroxy-H-phosphinic acid by TMSCl and attack of activated intermediate 21,22 4 to the protonated diimine giving an α-imino-α′-hydroxyphosphinic acid intermediate 5 which undergoes subsequent hydrolysis in the workup to the α-amino-α′-hydroxyphosphinic acid compound (Scheme 4).…”

New Double-Chain and Aromatic (α-Hydroxyalkyl)phosphorus Amphiphiles

“…In all cases, the presence of the two diastereomers in the final product was confirmed by 13 Following the idea of preparing new (a-hydroxyalkyl)phosphorus amphiphiles of enhanced hydrophobicity, bearing one or two alkyl chains, we decided to prepare a new series of long chain aromatic aldehydes which could be further used to prepare phosphorus amphiphiles using the phosphorylation reactions described previously (vide supra).…”