Hydrophosphorylations aldehydes

Because organophosphorus compounds are important in the chemical industry and in biology, many methods have been developed for their synthesis [1]. This chapter reviews the formation of phosphorus-carbon (P-C) bonds by the metal-catalyzed addition of phosphorus-hydrogen (P-H) bonds to unsaturated substrates, such as alkenes, alkynes, aldehydes, and imines. Section 5.2 covers reactions of P(lll) substrates (hydrophosphination), and Section 5.3 describes P(V) chemistry (hydrophosphorylation, hydrophosphinylation, hydrophosphonylation). Scheme 5-1 shows some examples of these catalytic reactions. 

The aforementioned type of complex was also useful to prepare chiral a-amino phosphonates 46, which are a-amino acid mimics with interesting biological activities (73-93% yield, 81-87% ee) [52]. The same enantioselective Kabachnik-Fields hydrophosphorylation starting with aldehydes 9, dialkyl phosphites 45, and anilines 38 could be performed using chiral imidazolidine-type ligands in combination with a zinc salt (Scheme 11.18) [53]. 

Scheme 8.65 Hydrophosphorylation of aromatic aldehydes using [Ti]/cyclohexyl diol catalytic...

Scheme 8.67 Hydrophosphorylation of aromatic aldehydes using Sharpless catalyst...

Scheme 8.70 Proposed mechanism of hydrophosphorylation of aldehydes using ALB catalyst...

Scheme 8.73 Hydrophosphorylation of aldehydes using (/ )-Al(salalen) complex...

Catalytic hydrophosphorylation of aldehydes was studied by Katsuki et al. with optically active salalen ligands (Scheme 8.73) [185, 186]. Excellent yields (up to 96%) and enantiomeric excess (up to 96% e.e.) were achieved in the addition reaction. An efficient catalyst was developed for enantioselective reactions with both aromatic and aliphatic aldehydes (up to 84 and 86% e.e., respectively) [187]. 

Feng et al. have reported highly enantioselective hydrophosphorylation of aldehydes catalyzed by aluminum complexes with tridentate Schifif base (Scheme 8.74) [188]. Excellent yields (up to 96%) and enantiomeric excess (up to 97%) were found in the addition reaction. Same authors have also studied asymmetric hydrophosphorylation of aldehydes catalyzed by bifunctional chiral aluminum complexes [189] and Lewis acid-catalyzed hydrophosphonylation of ketones [190]. 

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