Synthesis of PEG-iridium conjugates and their use as hydrogenation catalysts in a water/substrate two-phase medium

New syntheses of PEG-(OCH2C5H4N)(2) and PEG-(OC6H4PPh2)(2) (PEG: poly(ethyl ene glycol)) conjugates are reported. An iridium hydrogenation catalyst 1, is shown to catalyze hydrogenation in a water/substrate two-phase system. A ttachment of 1 to PEG to make 2 and 3 succeeds in making the complex water- soluble and allows it to retain some of its catalytic ability, but leads to micelle formation that inhibits the separation of organic and aqueous phas es. (C) 2001 Elsevier Science B.V. All rights reserved.