An easy and practical synthetic route to electron rich water soluble ligands:: α-aminomethylation of trishydroxymethylphosphine

Hydrophilic aminomethylphosphines 6a-e were prepared in excellent yield by the condensation of P(CH2OH)(3) (THP) with a variety of easily accessible water soluble secondary amines, such as sarcosine (5a), N-methyltaurine (5b), N-methylethanolamine (5c), diethanolamine (5d) and 3-(N-butylamino)propanesulfonic acid sodium salt (5e). All products 6 are highly water soluble and are stable in air as well as under a wide pH range. The basic character of 6a-e has been proven by titration and by infrared analysis of the nu(CO) A(1) frequencies of their corresponding nickel complexes 7a-e of the type Ni(CO)(3)L. (C) 2000 Elsevier Science Ltd. All rights reserved.