P III Tertiary Diazaphospholidines

2- diazaphospholidines are diaminophosphines that bear the N-P-N motif in a five-membered ring. They are easy to prepare and remarkably stable towards oxygen and water. Their synthesis is based on the displacement of two leaving groups (chlorine or dimethylamino groups) by a chiral secondary 

In an overwhelming majority of cases the diamine 1 is (S)-2-(anilino-methyl)pyrrolidine (Ar = Ph), easily obtained from L-glutamic acid and nowadays commercially available. 

The absolute configuration of the phosphorus atom is commonly indicated by the synlanti notation referring to the relative position of the exocyclic substituent at the P atom with respect to pyrrolidine ring. 

From Table 3.1 it can be seen that both monodentate (entries 1-24) and P,N-bidentate (entries 25 32) ligands can be prepared. Entry 33 depicts a polymer-bound diazaphospholidine, prepared by reaction of 4 with poly(p-hydr-oxystyrene). The stereoselectivity is often very high towards the thermodynamic anti epimer but sometimes significant amounts of the other epimer at the phosphorus atom are obtained (entries 9, 12, 13, 17, 21 and 32). The observed selectivity suggests that a dynamic kinetic resolution takes place during the reaction of 4 with alcohols or amines.  

Breeden and Wills reported that SEMI-ESPHOS ligand is obtained as a 

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