Controlled oxidative addition of amino acid esters to Rh(I)

The new sterically demanding phosphine 2-(di-o-tolylphosphino)phenol was pr epared and used to create a series of eaters with N-acylated amino acids. T he phosphine-containing esters react within 30-60 min at room temperature w ith [(mu-Cl)Rh(cyclooctene)(2)](2) to give products of oxidative addition o f the ester carbonyl-oxygen bond to the Rh center. The N-acyl carbonyl oxyg en is bound to the Rh in these initial adducts, but is displaced upon addit ion of PMe3. Remarkably, both initial products and their PMe3 adducts are f ormed as single five-coordinate diastereomers in essentially quantitative y ields. (C) 1999 Elsevier Science S.A. All rights reserved.