Diphosphines aminophosphines

Although the vast majority of centrally chiral diphosphine ligands to be employed in enantioselective rhodium-catalyzed hydroborations possess -symmetry, there are a few examples of ( -symmetric diphosphine ligands. Buono prepared bis(aminophosphine) ligands 35-38,81 while Bianchini reported (R, i )-BDPBzP 39 (Figure 5).82... 

Some data are also available on the effect of the structure of the phosphine or diphosphine on the optical yield in the asymmetric hydrocarbalkoxylation of 2-phenyl-1-propene (24) (see Table III). The best optical yield was obtained using 2,2-dimethyl-4,5-bis(dibenzo-phosphol-5-ylmethyl)-l,3-dioxolane as the chiral ligand. Much lower optical yields were obtained using aminophosphines or monophosphines. 

P NMR chemical shift data have been used extensively to confirm double bond formation in phosphaarsenes and diphosphenes. The P chemical shift range for these compounds is typically from -1-500 to -1-700 ppm (85% H3PO4). The shifts are among the lowest known in P NMR. P NMR chemical shifts for phosphinoarsines are similar to those for diphosphines and aminophosphines. ... 

NH2CH(R)CH2PR R". The aminophosphine is an intermediate ligand between a diamine and a diphosphine. The optical activity of such aminophosphine complexes can be compared with that of diamine complexes studied extensively. 

---